From January to December 1993, 3,385 bulk milk samples were collected from 293 herds in Inchon area. Standard plate counts(SPC) and somatic cell counts(SCC) were performed by the method of milk collection, the situation of raising management and monthly. The results obtained are summarized as follows : 1, Annual average SPC and SCC were respectively 638,000 cfu /mm and 647,000 cells /mm. SPC showed an abrupt decrease from January-1,088,000 cfu /mm to December-279,000 cfu /mm, but SCC showed a slow change from January-1,017,000 cells /mm to December -673,000 cells /mm 2. Variation on milk quality(annual average SPC) was shown a wide difference between everyday collection-575,000 cfu /mm and every other day collection-1,243,000 cfu /mm ac-cording to frequency of milk collection from dairy farms. However, there was a little difference In SCC. 3. In the raising scale, average SPC were the lowest in 16~25mi1king cows, and average SCC were the lowest in above 25milking cows. 4. According to types of milking machine, average SPC and SCC of dairy farms that are equipped with pipeline system were respectively 361,000 cfu /mm and 591,000 cells /mm. Those of dairy farms with bucket system were 549,000 cfu /me and 559,000 cells /mm. 5. In the types of management, average SPC an SCC of dairy farms with hired herdsman were 288,000 cfu /mm and 559,000 cells /mm. Those of dairy farms with self-management were 526,000 cfu /mm and 568,000 cells /mm.