The objectives were to investigate the factors (age, sex, breed and season) affecting the occurrence of calf diseases. In this study 497 cases of 0 to 3 months of age from three different farms were investigated. Calf in Savar Dairy farm (n=249), Talbag Dairy Farm (n=85) and BAU Dairy Farm (n=163) were included from April 2011 to March 2012. The occurrence of diseases were classified on the basis of breed (Local and Cross), age (≤ 3 weeks and >3 weeks), sex (Male and Female) and season (Spring, Summer, Rainy and Winter). The overall diseases were diarrhoea (20.3%), anorexia (9.7%), fever (9.1%), naval ill (8.0%), malnutrition (7.7%), indigestion (6.7%), traumatic injury (5.4%), dysentery (5.0%), myiasis (4.6%), pneumonia (3.4%), alopecia (3.4%), atresia ani (3.2%), hernia (2.8%),... constipation (2.6%), abscess (2.2%), conjunctivitis (2.2%), lameness (1.8%), FMD (1.2%) and blot (0.6%). The cases of diarrhoea was higher (20.5%) than that of other diseases. The occurrence of diseases was highly significant (p<0.01) in crossbred calves (77.3%) than that of local bred (22.7%). Cases of diseases were higher in male calves (51.7%) than that of female calves (48.3%) but the variation was insignificant (p>0.05). The effect of breeds on diseases were found significantly (p<0.05) higher in ≤ 3 weeks (55.1%) than that of > 3 weeks of age (44.9%). The occurrence of diseases in calves was significantly (p<0.05) higher in rainy season (36.0%) followed by the summer (31.0%), winter (22.1%) and lowest in spring (10.9%). The results demonstrate significant effect of breed, age and season on the occurrence of diseases in calves.