Milk is a food that inherently favors the microbial growth. There are many sources of contamination of milk including the cows itself, the environment water, milking processes and equipments. The varied routes for the introduction of pathogens into milk preclude the production of milk that can be guaranteed to be safe for human consumption. The objective of this study was to evaluate the microbiological safety and to detect mastitis in milk that sold in Jimma town, south western Ethiopia. A total of 90 samples were collected form some randomly selected restaurants in the town. Standard methods were used for the enumeration of aerobic mesophillic bacteria, coliforms, aerobic bacterial spores, lactic acid bacteria, yeast and molds. Isolation and identification of the most important mastitis bacterial pathogens (Staphylococcus aurous and Streptococcus agalactiae) were also done. The data was analyzed by using SPSS version 15 and presented by using tables and graphs. The result of the study showed that the mean microbial counts were dominated by aerobic mesophilic bacteria (7.5±0.8), lactic acid bacteria (6.6±0.6), coliforms (5.9±0.4), yeasts (5.1± 0.5) aerobic bacterial spores (4.2±0.4) and moulds (3.7±0.6). On the other hand, two most important mastitis pathogens were isolated and identified. Generally the microbial safety of milk sold in Jimma town was poor and it calls for special attention especially those concerned bodies inhabit in the town.