The aim of this study was to determine the effect of the temperature-humidity index (THI) on selected milking parameters in AMS. Three dairy farms with AMS were included in the monitoring. The monitoring period was three years. The selected parameters were as follows: milk production.cow-1.day-1, milking frequency.cow-1.day-1, milking time.cow-1.day-1, THI. The results showed that heat stress (THI above 72) negatively influenced average daily milk yield and milking time. These parameters showed significantly (p< 0.05) lower values in mild-moderate zone (MMS) zone than in no heat stress zone (NS) and heat stress threshold zone (ST). The difference in milking frequency per day was not found to be significant, although in the MMS zone dairy cows were milked less often.