Practical experience suggests that music can have a positive effect on the welfare of dairy cows, which for some other animal species has been shown in earlier studies. Music could, furthermore, be a useful tool to support, for example, daily milking routines. In this pilot study we explored effects of music inside an automatic milking system (AMS) on cows’ milk yield and behavior. The experiment was conducted on a Finnish dairy farm with 56 cows in loose housing. Over two 2-day periods without and with selected music pieces played inside the AMS, data on daily milk yield (DMY), selection gate passing frequency (GP), milking frequency (MF), and milking interval (MI) were recorded. For analyses, data of 17 Holstein-Friesian cows were used. At cow level, mean values over repeated measurements without and with music were calculated, and analyzed by paired t-tests (DMY, MF) or Wilcoxon tests (MI, GP). During intervals with music versus without, cows passed the selection gate more often (15.8 versus 13.8) and had higher MF (3.0 vs. 2.8). No differences were found in MI (07:49:21 vs. 08:37:38) and DMY (36.5 vs. 37.0). The latter might be explained by a ceiling effect. Overall, the results suggest that the investigated sample of cows perceived the selected music as attractive and that playing music might be a practical tool to reduce necessary efforts of driving cows to milking.