A proper transition from gestation to lactation is critical to optimize health and milk production in the subsequent lactation. While some studies have suggested that the administration of nonsteroidal anti-inflammatory drugs after parturition resulted in increased milk production of lactating dairy cows in conventional dairy herds, others failed to show an effect. The objective of this study was to assess the effects of oral administration of acetylsalicylic acid after calving on milk yield, milk protein, milk fat and somatic cell count (SCC) in lactating dairy cows under organic management. This study was performed in 3 organic dairy herds. Cows were block by parity and calving ease (eutocia; dystocia) at parturition, and were randomly allocated to 2 treatment groups: 1) ASP (n = 278): within 12 h after parturition cows received 4 consecutive treatments every 12 h with acetylsalicylic acid (100 mg/kg; 2 boluses); or 2) placebo (PLC, n = 285): within 12 h after parturition cows received 4 treatments every 12 h with gelatin capsules (2 capsules) filled with water. Data from the first 5 DHIA tests after parturition were recorded. In addition, daily milk yields were collected for the first 30 DIM from a subset of cows (ASP = 110; PLA = 122). The data were analyzed using ANOVA by the MIXED procedure of SAS as a randomized block design with repeated measures. Cows in the ASP group had higher (P = 0.048) daily milk yield (26 ± 0.88 kg/d) when compared with cows in the PLC group (24 ± 0.79 kg/d) during the first 30 DIM. Similarly, cows in the ASP group had higher milk production on the first 5 DHIA tests compared with PLC cows (P < 0.05; ASP = 31 ± 0.43 kg/d; PLC = 30 ± 0.43 kg/d). Additionally, ASP cows had lower SCC (P < 0.05; ASP = 153 ± 241 × 10³ cells/mL; PLC = 207 ± 324 × 10³ cells/mL) during the first 5 DHIA test compared with PLC cows. No difference was found in the percentage of milk fat and protein between groups. The results from this study suggest that treatment with ASP after calving may improve milk yields and decrease SCC during the first 5 DHIA tests. Further research aimed to evaluate strategies to improve the transition from gestation to lactation are required.