The objective of the present study was to examine the effects of Catharanthus roseus (C. roseus) extract (leaves and roots) on growth performance and microarchitecture of the small intestine in Cobb 500 broilers. One hundred and seventy-five, 1-day-old chicks were randomly divided into seven treatment groups (n = 25/group) with five replicates (n = 5/replicate). Birds in group 1 served as a control and were offered a corn soybean-based basal diet only. The birds in groups 2, 3, and 4 were fed the same diet supplemented with 0.05%, 0.1%, and 0.2% aqueous leaf extracts of C. roseus. Whereas, groups 5, 6, and 7 were provided the diet supplemented with 0.05%, 0.1%, and 0.2% aqueous root extracts of C. roseus, respectively, for 35 days. Supplementation of C. roseus extracts did not improve body weights, weight gain, feed intake, and feed conversion ratio. Relative weights of viscera remained unchanged except that of gizzard and pancreas which were lower (P < 0.05) in 0.1% ALE supplemented birds. The microarchitectural attributes including villus height, width, surface area, crypt depth, and the ratio of villus height to crypt depth were higher (P < 0.05) in the 0.05% ALE supplemented group. In conclusion supplementation of C. roseus extracts did not improve growth performance but improved gut histomorphometric parameters of the small intestine in broilers.