Daily pasture allowance (PA) is defined as the product of pregrazing pasture mass and offered area per animal. Determining the optimum PA is not an easy task because it depends on, and varies with, pasture and animal characteristics; however, it is very important because is directly related to farmer decisions. The objective of this study was to evaluate the effects of PA on milk yield and composition of Holstein cows during autumn. The experiment was conducted at the Mario Antonio Cassinoni Experimental Station (Universidad de La República), Paysandú-Uruguay, during autumn from April 9 to June 3, 2010. Eighteen hectares of pasture with Tall Fescue (Festuca arundinacea) intercropped for the second productive year with legumes white clover (Trifolium repens) and bird’s-foot-trefoil (Lotus corniculatus) were utilized in this study. Total area was divided into 4 blocks of 4.5 ha, and each block was divided into 3 grazing paddocks of 1.5 ha. Thirty-six Holstein cows calving in the autumn were allocated to blocks considering: calving date, body weight, and body score. Treatments consisted of 3 pasture allowances as follows: high (HA, 38.4 kg DM/cow/day), medium (MA, 30.3 kg DM/cow/day), and low (LA, 26.8 kg DM/cow/day). Means were compared using Tukey test (P ≤ 0.05). There was an effect of PA on the milk yield per hectare and milk yield per cow. The highest production per hectare was observed in LA (438 L/ha/day) and the lowest in HA (314 L/ha/day). On the other hand, cows increased individually milk production in HA and MA (25.6 and 26.6 L per cow/day, respectively). The content of protein and fat in milk did not differ among treatments. The yield of milk protein from cows in the LA management decreased (718 g/cow/day) compared with MA (846 g/cow/day), but did not differ from HA (820 g/cow/day). Different pasture allowances affected milk production and composition of dairy cows. The LA provided better conditions for milk yield per area, likely due to the better grazing efficiency. Thus, farmers may increase stocking rate to reach higher milk production when lactating dairy cows graze mixed pasture swards.