The present rat balance study investigated Ca availability from the whole indigenous small fish species, mola (Amblypharyngodon mola) from Bangladesh and from skimmed milk. Four groups of six young male rats each were fed ad libitum with diets containing either small fish or milk, at 100 or 160 g crude protein/kg diet dry matter. The study was conducted for 28 d and faeces and urine samples were collected in two balance periods: days 8–14 and 22–28. The Ca and N contents of the diets, faeces and urine were analysed. Ca intake, fractional Ca absorption and Ca retention in relation to N retention were measured. Digestibility and protein utilization of the experimental diets, weight gain of the rats, femur bone weight and mineral composition as well as bone alkaline phosphatase activity were also determined. It was concluded from the values of these variables that Ca from small fish with bones was available and appeared to be a useful Ca source in rats, though perhaps not as available as Ca from milk. This study suggests that small fish with bones may be an important source of Ca in human diets. Promotion of the production and consumption of small fish in population groups with low intakes of milk and milk products should therefore be encouraged.