Abstract: The present study was carried out to investigate the factors affecting keeping quality of raw milk in lactating cows in Ampara District of Sri Lanka. In this study, a total of 110 raw milk samples were randomly collected from 7 milk chilling centers and details on milking practices were collected from the farmers through structured questionnaire and interview. Milk samples were collected aseptically from milk cans and dispatched to laboratory for keeping quality test. Result showed that 42 % of the collected milk from farmers had poor keeping quality. The buffalo milk showed a significantly poor keeping quality (p< 0.05) compared to that of cow milk. Also the poor keeping quality was higher in milk collected from plastic milk containers (76.1%) compared to that of metallic containers (37.8%).Other factors that significantly contributed to poor keeping quality were presence of contaminants (73.5%),milk from cow in late lactation (63.1%), higher fat percentage in milk (66.6%), the time interval between milking to chilling (92.8%) and poor hygienic practices (76.4%).