Pearl millet is a staple food for millions, particularly vital for food security in the Sahel region. In Senegal, where it is widely cultivated, yields are low, and planting densities are considered very low, with approximately three plants per m². Previous research in experimental stations showed a positive crop response when sowing density was doubled, with no significant effect from the varieties tested. This raised key questions: i) Are the varieties currently used by farmers tolerant to such intensification? ii) Can higher sowing density increase yield on farms, i.e., under rainfed and low fertility conditions? Are rainfall and environmental conditions critical factors in this response. To address these questions, we set up on-farm trials in three communities along a rainfall gradient from 350 to 900 mm during the 2023 and 2024 rainy seasons. In each location, 10 farmers sowed a certified and a local pearl millet variety, each at two different densities (3 or 6 plants per m²). Farmers were asked to manage the experimental fields as they typically would, with no special care or changes to their usual practices. Stover and grain yields were measured at maturity for each variety and density treatment. The high-density treatment significantly increased both stover and grain yield by an average 30% across community, with a 21-38% range of response. Density response was stronger in locations with higher evaporative demand, shown by a significantly negative relationship between the density effect on yield and the rainfall and a positive relationship with the radiation received in the different localities, confirming previous evidence from experimental stations. These findings are promising for achieving sustainable intensification of pearl millet cultivation, toward more food security for the region. Counter-intuitively, increasing density could also be an option to better cope with drier environments.