Immunization of dogs against rabies plays a very vital role in reducing mortality due to rabies in humans as well as in animals. In this context, it is important to know whether a representative group of canines; specially Sri Lankan local breed/mongrel breed have antibody titres above the protective level recommended by the WHO following anti-rabies immunization and also whether the antibody titres are maintained above the protective level until the time of annual booster. Healthy domestic, stray dogs and puppies (N = 510) in Kalutara district, Sri Lanka were recruited initially and allocated into 8 groups based on pre-established criteria. A monavalent (inactivated) vaccine recommended by the Government Rabies Control Programme was used to immunize all recruited canines. On the day of vaccination 3-5 ml of venous blood (D0) was collected from each animal and post immunization blood samples were collected on days 30, 180, 360 (D30, D180 and D360). Rapid Fluorescent Focus Inhibition Test (RFFIT) was used to determine the virus neutralizing antibody titres in serum samples, at the Department of Rabies Research and Vaccine Quality Control, Medical Research Institute (MRI), Colombo 08. Total number of blood samples analyzed was 1520 collected from 380 canines that were available until D360 after immunization. The Ethics approval for the study was obtained from the Ethics Review Committees of the Faculty of Medicine, Colombo and MRI. The number (and percentage) of canines in Groups A to H that had antibody titres below the protective level of 0.5 IU/ml on D0, D30, D180 and D360 are indicated in table 1 (Mean antibody titres are not shown here). This is the first descriptive and comparative study involving a representative group of canines done in Sri Lanka. This indicates that a single dose of anti-rabies immunization fails to generate a protective level of immunity which lasts until 1 year in 40.42% of stray dogs in Group A and 57.14% of domestic dogs in Group D. The pattern of antibody titre development in adult domestic dogs in Groups E and F seems to be closely similar irrespective of regularity in immunization. Almost all puppies in Groups G and H need more than one immunization until the time of annual booster. It is evident that maternal antibodies do not protect puppies against rabies until the first anti-rabies immunization.