The activity of many species of anurans is affected by variables such as rainfall, air temperature, photoperiod, and food resources. In this study we investigated the activity period of the toad Melanophryniscus moreirae and tested the influence of photoperiod and air temperature on the number of toads seen active. The study was carried out between March 2004 and December 2005 on the elevated area of Parque Nacional do Itatiaia (PNI) southeast Brazil, at elevations varying from 2300 to 2400 m. Twenty 10 × 10 m plots were established as sampling units. To evaluate hourly activity, the plots were visited between 05:00 and 24:00 h, one plot at each hourly interval. Hourly activity was estimated based on the total number of toads seen at hourly intervals, across the study period. Annual and reproductive activities were estimated based on the total number of individuals and number of amplectant pairs, respectively, found within a month. Melanophryniscus moreirae is a strictly diurnal species with two peaks of activity, one in the morning and another in the afternoon. Along the study, toads were only seen from September to April. Photoperiod had a significant effect on monthly activity. The reproductive activity is restricted to the period from September to December.