Robotic milking systems (RMS) have attracted growing interest from dairy producers in the last few years in the United States, but the amount of research data available is limited. It has been observed that it takes some time for cows to adjust to the RMS, especially primiparous cows. Therefore, the objective of this study was to compare daily milk yield and milking frequency (number of milkings/d) between primiparous cows introduced to the RMS without any previous exposure (2016) and cows trained to access the RMS before calving for the first time (May–Nov 2017). The training was performed in a case study dairy farm 2×/d for approximately 15 d pre-partum by physically bringing cows to the RMS milking station, where they were offered 1 kg of a concentrate pellet/visit. Eight stages of lactation were evaluated: 1–7, 8–14, 15–21, 22–30, 31–60, 61–90, 91–150, and 151–210 DIM. Data were analyzed using PROC MIXED (SAS 9.4); stage of lactation and year as fixed effects and cow as random effect. Daily milk yield (n = 31,828 cow-d) was greater for trained cows at all the stages of lactation; a stage × yr interaction was detected (P < 0.001). Milk yield (not trained and trained cows, respectively) was 16.6 and 19.3 kg (1–7 DIM); 23.0 and 28.6 kg (8–14 DIM); 27.7 and 32.3 kg (15–21 DIM); 30.2 and 35.7 kg (22–30 DIM); 33.4 and 38.3 kg (31–60 DIM); 35.4 and 38.3 kg (61–90 DIM); 34.7 and 37.2 kg (91–150 DIM); 32.7 and 36.4 kg (151–210 DIM). Milking frequency followed the same pattern and was greater at all stages of lactation for trained heifers; a stage*yr interaction was detected (P < 0.001). Number of milkings/d (not trained and trained cows, respectively) was 1.82 and 2.12 (1–7 DIM); 1.88 and 2.62 (8–14 DIM); 2.05 and 2.94 (15–21 DIM); 2.16 and 3.27 (22–30 DIM); 2.24 and 3.44 (31–60 DIM); 2.45 and 3.12 (61–90 DIM); 2.51 and 3.15 (91–150 DIM); 2.46 and 3.01 (151–210 DIM). Training nulliparous cows to the RMS before calving appeared to affect milk yield and milking frequency. However, more research is yet needed to further investigate this management practice on RMS farms.