When six cows were milked every 4 h over 48 h the average milk yield per cow increased by 1O·7% for the last 24 h period compared with the previous 5 d. Milk composition was similar to pre-experimental values although fat content was 0·5% lower in the last 24 h. The somatic cell count rose to twice the pre-experimental value over the first 24 h but was not significantly different by the second 24 h. It appears that cows responded quickly to an increased frequency of milking and milk of an acceptable composition was produced. This has implications for management of milk production where quotas are in operation and for robotic milking systems.