Diamond pythons (Morelia s. spilota) are large (to 3 m) snakes of temperate-zone coastal eastern Australia. Foraging behavior was studied by observation of telemetered snakes, and diets determined by dissection of museum specimens and collection of fecal samples from wild-caught snakes. Five adult snakes monitored in the field by radiotelemetry were found to be ambush foragers. In summer, telemetered snakes spent more than 80% of their time coiled, usually in a disinctive ambush posture near mammal trails. Telemetered snakes found feeding had occupied the site for at least a day beforehand. The diet of adult diamond pythons consisted almost entirely of mammals (91% of 44 records), mainly Rattus rattus and R. fuscipes (52%). Birds (9%) were taken infrequently. Juveniles ate mainly mammals (69%) and reptiles (23%). Larger snakes consumed larger prey. Hatchlings in captivity showed a preference for copper-tailed skinks, Ctenotus taeniolatus, but would also take newborn mice. Feeding occurred mainly in late spring, summer and early autumn. In terms of feeding biology, diamond pythons may be more similar to viperid snakes of other continents than to the elapids or colubrids with which they are sympatric.