The present study was aimed to determine the effect of different types of milk and kefir grains or starter cultures on the chemical properties, and microorganism counts of kefir samples. The type of milk had a significant effect on the acidity, dry matter, protein, and CO2 values. Acidity and CO2 values increased during storage period, while dry matter, fat and protein contents decreased. However, the type of milk had no significant effect on Lactobacillus, Leuconostoc and yeast counts. In the samples produced using starter culture microorganism counts except those of L. acidophilus of the samples increased (p < 0.05) during the 14 days of storage. Higher Lactobacilli (8.52 log cfu/ml) and Lactococci (8.84 log cfu/ml) was found in kefir produced using buffalo milk and starter culture in 21 days of storage, while higher L. acidophilus (6.41 log cfu/ml) was found in kefir produced using cow milk and starter culture. In general, due to the higher dry matter and protein content and yeast population, kefir made from buffalo milk may be preferred.