A survey of the richness, abundance and species composition of Sphingidae (Lepidoptera) was performed in a fragment of Atlantic Rainforest at the Serra do Japi Biological Reserve, Municipality of Jundiaí, state of São Paulo, Brazil. Sampling was done monthly, on 2 consecutive nights, from Dec 2011 to Oct 2012, totaling 264 hours of sampling effort. The hawkmoths were attracted by a light trap. Our results were compared with data from a survey of Sphingidae carried out in another fragment of Atlantic Rainforest, i.e., at the Boraceia Biological Station, Municipality of Salesópolis, São Paulo. Richness estimators, rarefaction curves and rank/abundance plots were used to describe the assemblage sampled in this study and to compare it with the data set from Boraceia. We collected 462 specimens, members of 3 subfamilies, 5 tribes, 18 genera and 39 species. Callionima parce (Fabricius) was the most abundant species, comprising 33% of the individuals. Orecta lycidas (Boisduval), an under-sampled species in the Atlantic Rainforest, was recorded for the first time in the area of Serra do Japi. The assemblage showed lower species richness and evenness than the assemblage at Boraceia, probably due to differences in climate, vegetation and size of the forest fragment in which the reserves are situated. Nevertheless, our results emphasize the importance of the Serra do Japi Biological Reserve for the fauna of Lepidoptera of the Brazilian Atlantic Rainforest.