A case control study was conducted to ascertain the prevalence of clinical diseases and/or clinical conditions of 3670 sick pet dogs presented to the Central Veterinary Hospital (CVH), Dhaka during the one year period from January to December 2009. A total of 57 types of diseases and conditions in 17 categories were recorded in these pet dogs and their variation in prevalence were analyzed on the basis of age, gender, season and breeds of dogs. The prevalent diseases and/or conditions from low to high rates included glaucoma (0.05%), babesiosis ( 0.08%), sinusitis (0.08%), tetanus (0.08%), spaying (0.14%), nail injury (0.19%), nephritis (0.19%), cataract (0.25%), metritis (0.25%), poisoning (0.33%), orchitis (0.35%), rabies (0.35%), pus in antrum (0.41%), purulent cough (0.46%), alopecia (0.52%), pharyngitis (0.52%), transmissible venereal tumor (0.54%), cystitis (0.52%) phimosis (0.52%), paraphimosis (0.60%), stomatitis (0.63%), pneumonia (0.63%), mastitis (0.71%), otitis (0.73%), taeniasis (0.74%), abscess (0.82%), anal gland disease (0.82%), dystocia (0.84%), conjunctivitis (0.90%), lice infestation (0.90%), lameness (0.95%), ottorrhea (1.06%), uterine prolapse (1.31%), posthitis (1.31%), dental disorders (1.34%), metabolic diseases (1.36%), protrusion of eye ball (1.44%), canine distemper (1.61%), liver disease (1.72%), nutritional deficiency diseases (1.77%), infertility (1.80%), coccidiosis (1.93%), toxocariasis (1.93%), urinary tract infection (2.10%), accidental wounds (2.32%), haematuria (2.34%), bronchitis (2.81%), arthritis (2.94%), dermatomycosis (3.30%), aspiration pneumonia (3.32%), mange (3.76%), echinococcosis (3.92%), dermatitis (4.99%), diarrhea (5.21%), ancylolostomiasis (6.20%), flea infestation (9.84%) and tick infestation (11.88%). Age-wise overall prevalence of clinical diseases revealed significantly (p <0.05) highest in age group above 36 months (48.12%) compared to that in 7 to 36 months (34.33%) and up to 6 months (17.55%) age groups of pet dogs. The significantly (p <0.05) highest prevalence of diseases and/or clinical conditions was recorded in local (33.35%) and German shepherd (22.53%) breeds of pet dogs in comparison to that in their counterpart breeds of Lhasa-Apso (7.57%), Greyhound (7.11%), Doberman (6.34%), Samoyed (6.23%), Dachshunds (5.20%), Spaniel (3.37%), Spitz (3.07%) and Poodle (3.18%). Results from season-wise analysis of overall prevalence of diseases and/or clinical conditions in pet dogs did not differ significantly (p >0.05) among spring (21.53%), summer (25.80%), autumn (22.83%) and winter (29.84%). The highest prevalence of arthropode infestation (22.62%), followed by intestinal parasitic diseases (14.80%) and diarrhea (5.20%) suggest a poor husbandry of these pets in Dhaka. Results of this study indicate that the risk of zoonotic infection by canine intestinal parasite may be high in Bangladesh.