We compared breeding ecology, density, and reproductive success of Roadside Hawks (Buteo magnirostris) in two Guatemalan study areas during 1993 and 1994. Primary forest supported 1.15 territorial pairs/km² whereas a slash-and-burn farming landscape supported 1.41 territorial pairs/km². All nests (n = 32) were in emergent trees. Hawks nested selectively in low canopy, seasonally inundated primary forest, and spacing of nests was related to the distribution of this forest type. Pairs did not nest selectively in a particular habitat in the farming landscape, but nested in isolated, emergent trees. Nest success (proportion of attempts that produced ≥1 fledgling) was 0.17 in the forested area and 0.30 in the farming landscape. Productivity (fledglings per territorial pair) was 0.08 in the forest and 0.32 in the farming landscape. Incidence of non-nesting by territorial pairs was greater in the forest (50%) than in the farming area (20%). The overall rate of nesting by territorial pairs was 65%. The most frequently identified cause of nest failure in the farming landscape was human persecution, while in the forest it was predation. Prey delivery rates did not differ significantly between habitats.