The present study was undertaken to estimate the profitability and resource use efficiency under different farm size groups of maize production. In total, 65 farmers (30 small, 30 medium and 5 large) were randomly selected from five villages of Bogra district. Both tabular and statistical analyses were applied in this study. Cost and return analysis reveal that maize is a profitable crop for all categories of farmers. On an average per hectare total cost of maize production was estimated at Tk 46278 for all farmers and Tk 41263, 53554 and 48715 for small, medium and large farmers, respectively. Again, gross margins from maize production were estimated at Tk 67592, 64694 and 74089 for small, medium and large farmers, respectively. However, net returns for the farm size groups of small, medium and large were calculated at Tk 57823, 53895 and 64138 per hectare, respectively. BCR was the highest (2.40) for the small farmers followed by medium (2.01) and large (2.32) farmers, respectively. Cobb-Douglas production function analysis indicated that out of nine variables, the effects of using seed, manure, fertilizer, irrigation and insecticide had significant impact on gross return from maize production for all farmers. Efficiency analysis indicated that most of the farmers inefficiently used their inputs. The findings of the study revealed that large farmers earned higher profit than those of small and medium farmers. The study also indicated some problems and constraints of maize cultivation and suggested some recommendations to improve maize production with a view to increasing the household income and employment opportunities of the farmers.