The reproductive characteristics of many tropical amphibian species are poorly known, and the populations of many of these species are in decline. They occur in a variety of habitats and microhabitats. We investigated the reproductive biology of a tropical salamander, Bolitoglossa paraensis, in mature forest habitat in the Gunma Ecological Park, in the Brazilian state of Pará. During 12 nocturnal surveys between December 2005 and May 2007, we collected 104 salamanders (59 females/45 males) in order to compare microhabitat use in adults and juveniles, and assess the reproductive condition of males and females in relation to body size. Maturity was determined in females by the presence of enlarged, yolk-rich follicles >1.5 mm in diameter, and in males by the presence of distinct mental glands. A total of 18 females and 14 males were considered adult (mature). Adult females were significantly larger and heavier than adult males. Microhabitat use was similar between adults and juveniles, with 67% of specimens being found on the upper surface of the leaves of broad-leaved understory plants at heights of 0.2–2.8 m above the ground. The remaining specimens were found on trunks and branches at heights of 0.5–2.2 m. Clutch sizes varied from 8 to 14 eggs, but there was no significant relationship with female body size (SVL). Adult males and females were active mainly during the rainy season. The abundance of adults was related significantly to precipitation levels, indicating greater activity levels during the rainy season. Bolitoglossa paraensis is similar to other tropical species of this genus in terms of sexual dimorphism and patterns of microhabitat use and reproductive biology.