The adaptation covers eight of the 24 tales and contains abundant nudity, sex and slapstick humour. Many of these scenes are present or at least alluded to in the original as well, but some are Pasolini's own additions.
The film sometimes diverges from Chaucer. For example, "The Friar's Tale" is significantly expanded upon: where the Friar leads in with a general account of the archdeacon's severity and the summoner's corruption, Pasolini illustrates this with a specific incident which has no parallel in Chaucer. Two men are caught in an inn bedroom having sex. One is able to bribe his way out of trouble, but the other, poorer man is less fortunate: he is tried and convicted of sodomy—it does not occur to the judge that such an act cannot be committed by one person alone—and is sentenced to death. As a foretaste of Hell, he is burned alive inside an iron cage ("roasted on a griddle" in the words of one spectator) while vendors sell beer and various baked and roasted foods to the spectators.
In Pasolini's version of the fragmentary "Cook's Tale", Ninetto Davoli plays the role of Perkyn in manner clearly inspired by Charlie Chaplin.
Set in England in the Middle Ages, stories of peasants, noblemen, clergy and demons are interwoven with brief scenes from Chaucer's home life and experiences implied to be the basis for the Canterbury Tales. Each episode does not take the form of a story told by different pilgrim, as is the case in Chaucer's stories, but simply appear in sequence, seemingly without regard for the way that the tales relate to one another in the original text. All the stories are linked to the arrival of a group of pilgrims at Canterbury, among whom is the poet Geoffrey Chaucer, played by Pasolini himself.
First Tale (The Merchant's Tale)
The elderly merchant Sir January decides to marry May, a young woman who has little interest in him. After they are married, the merchant suddenly becomes blind, and insists on constantly holding on to his wife' wrist as consolation for the fact that he cannot see her. While the two are walking in the January's private garden, May asks to eat mulberries from one of the trees. Taking advantage of her husband's blindness, she meets with her lover inside of the tree, but is thwarted when the god Pluto, who has been watching over the couple in the garden, suddenly restores January's sight. January briefly sees May and her lover together, but she convinces him that he has hallucinated.
Second Tale (The Friar's Tale)
A vendor witnesses two different men committing sodomy, both of whom are caught in the act. While one man manages to escape persecution by bribing the authorities, the other is sentenced to burn on a "griddle". During his execution, the vendor walks through the crowd selling griddle cakes. Afterwards, the vendor meets a summoner, and after the two vow to be friends, the vendor reveals himself to be the devil. The summoner then explains that he must collect money from a miserly old woman. When they meet the old woman, the summoner levies false charges against the old woman and tells her that she must appear before the ecclesiastical court, but says that if she pays him a bribe in the amount she owes, she will be excused. The old woman accuses him of lying, and curses him to be taken away by the devil if he does not repent. The summoner refuses, and the devil proceeds to take him to hell.
Third Tale (The Cook's Tale)
Perkin, A Chaplin-esque fool who carries a cane and wears a hat resembling a bowler, finds work polishing eggs. While his employer is away, Perkin is distracted by a group of men playing a dice game nearby, and joins them. He is soon discovered and fired. Perkin accompanies one of the men home, where he shares a bed with the man and his wife, who is a prostitute. Two police officers who Perkin evaded earlier discover him there, and Perkin is arrested and put in the stocks.
Fourth Tale (The Miller's Tale)
Nicholas, a young student, seduces Alison, the wife of a carpenter. In order to deceive the carpenter, Nicholas convinces him that a massive flood is about to occur, and claims that he, the carpenter, and Allison should all three wait in buckets tied to the ceiling rafters to escape drowning. While the carpenter waits in his bucket, Nicholas and Allison sneak away to have sex. Meanwhile, a youth named Absolon who has been flirting with Alison arrives asking for a kiss. Allison answers him by inviting him to climb up to her window and then farting in his face. Absolon runs to a blacksmith's shop where he borrows a hot poker, then returns to the carpenter's house and asks for another kiss. On this occasion, Nicholas goes to the window instead of Alison, and has his buttocks scalded. Nicholas then cries out for water, leading the carpenter to believe that the flood has arrived. The carpenter then cuts the rope holding his bucket in the air, and violently falls to the ground.
Fifth Tale (The Wife of Bath's Tale)
In Bath, a middle-aged woman's fourth husband falls ill during sex and dies soon after. The wife quickly decides to marry a young student, literally running from her late husband's funeral in one wing of a cathedral to her wedding in another wing. On their wedding night, the wife of Bath's fifth husband reads to her from a book denouncing the evils of women. The wife of Bath demands that he not tell her about her own business, and destroys the book. Her husband pushes her away, and she falls onto her back and moans on the floor. When he leans over to comfort her, however, she bites his nose. This episode is derived from the prologue to the Wife of Bath's Tale rather than the tale itself.
Sixth Tale (The Reeve's Tale)
In Cambridge, two students bring a sack of grain to a mill to be milled into flour. The miller tricks the youths by freeing their horse and switching their flour for bran while they chase after it. When they return with the horse, it is late in the evening, and the students ask to stay the night. The miller agrees to let them stay, and the two share a pallet bed next to one shared by the miller and his wife. During the night, one of the students seduces Molly, the miller's daughter, being careful not to wake the Miller. The miller's wife, meanwhile, gets up to urinate, and stumbles over the crib at the foot of her and the miller's pallet. Before she returns, the other student moves the crib to the foot of his own pallet, tricking the miller's wife into sleeping with him instead of the miller. The first student finishes having sex with Molly, and she confesses that she and father have stolen his flour. The student then gets into bed with the miller and tells him about his exploits with Molly, thinking that the miller is his companion.
Seventh Tale (The Pardoner's Tale)
One of a group of four young men is killed by a thief, spurning the others to seek out Death for themselves. The youths then encounter an old man, who they accuse of conspiring with Death in order to kill the young, and demand at knifepoint that they tell him where Death is located. The old man tells them to look around a nearby oak tree, where they find instead an abundance of treasure. While two of the youths wait by the treasure, a third leaves for town, returning later with three casks of wine, two of which he has poisoned. When he reaches the tree, the two youths drink the poisoned wine and then stab their companion.
Eighth Tale (The Summoner's Tale)
In the final tale, a gluttonous friar tries to extract as many donations as possible from a bedridden parishioner. The parishioner then offers him his most valuable possession, provided he promises to distribute it equally among all the friars. The parishioner claims that this possession is located beneath his buttocks. When the friar reaches down to retrieve the item, the bedridden man farts into his hands. That night, an angel visits the friar and brings him to hell, where Satan expels hundreds of corrupt friars from his rectum.
The film ends with the pilgrims arriving at the Canterbury Cathedral, and Chaucer at home writing the words "Qui finiscono i racconti di Canterbury, narrati solo per il piacere di raccontarli. Amen," meaning "Here ends the Canterbury Tales, told only for the pleasure of telling them. Amen:" a phrase that appears nowhere in the original Canterbury Tales.