Abstract: The study was conducted on the basis of semen sample collected from CCBSDF, Savar, Dhaka, RDCIF, Rajabarihat, Rajshahi and District AI Centre, Rajshahi over a period 1998 to 2003 to evaluate the effect of breed on dimensional characteristics of spermatozoa as well as correlation among the biometrical characteristics. The dimensional characteristics of spermatozoa were Head Length (HL), Head Breadth (HB), Head Shape (HS), Mid-piece Length (ML), Tail Length (TL) and total Sperm Length (TSL). A total of 915 spermatozoa from 71 bulls of six genetic groups were included in the study. The average for head length (HL), head breadth (HB), head shape (HS), mid-piece length (ML), tail length (TL) and total sperm length (TSL) were 9.164?0.53?, 4.703?0.38?, 1.958?0.16, 13.367?1.18?, 46.653?1.93? and 69.184?2.40?, respectively of 71 bulls. Genetic groups of 100%Friesian, 100%Sahiwal, 75%Friesian?25%Local, 50%Sahiwal?50%Friesian, 50%Friesian?50%Local and 100 Local had significant (p<0.05) effect on all the dimensional characteristics of spermatozoa. The highest HL (9.371?) was obtained for 100%Friesian with the lowest (8.759 ?) in 100%Local breed. Significantly highest HB (4.843?) was found in 50%SL?50%F with the lowest (4.539?) in 100%Local breed. The HS, ML, TL and TSL were found significantly highest in 100%Friesian breed (2.021, 13.627?, 47.591? and 70.591?, respectively) than 100%Local breed. The breeds of pure (exotic), cross-bred and pure local had significant (p<0.05) effect on dimensional characteristic of spermatozoa. Grossly, pure and cross-bred had significant (p<0.05) effect on dimensional characteristics except on head length. The head length of bull spermatozoa had significant positive correlation with HB, HS, TL, and TSL. Negative correlation was found also between ML, HS, and TL. Significant (p<0.05) positive correlation were also found between ML and TSL (r=.510; P<0.05) as well as between TL and TSL (r=.836; P<0.05). Results of the present tudy recommended that the genetic groups of 100%Friesian and 50%Sahiwal?50%Friesian had better performance of the dimensional characteristics of spermatozoa as well as Pure (exotic) and Pure breed had improved dimensional characteristics of bull spermatozoa.