INTRODUCTION. Yield of common bean is low at most countries. In 2005 the world average yield was only 735 kg ha^-1. There are some reasons for this low yield. One is the low population density used by producers for their bean plantations, principally in poor countries. To increase the plant population density (PPD) is a technical option for high bean's yields. OBJETIVE. To evaluate the effect of high plant population densities on the growth of common bean. MATERIALS AND METHODS. A type I of common bean (erected), Cv. Peruano, was planted in plastic pots (15 Ø x 50 cm) under the PPD of 500,000; 1,000,000; 1,500,000 and 2,000,000 plants ha^-1. To avoid plant competition for nutriments, the same amount of chemist fertilizer (20-10-10) was applied to each plant. Plenty of water was also applied to all pots. RESULTS AND ANALYSIS. Total dry matter was 5,610; 15,763; 16,877 and 16,280 kg ha^-1; while crop yields were 1,901; 3,032; 4,355 and 3,271 kg ha^-1, for the 500,000; 1,000,000; 1,500,000 and 2,000,000 plt ha^-1, respectively. The highest harvest index (HI) was measured for the lowest PPD (0.34). The 1,000,000; 1,500,00 and 2,000,000 plt ha^-1 had a HI of 0.19, 0.26 and 0.20, respectively. Although leaf area per plant was higher with the lowest PPD (1238, 907, 706 and 659 cm^-2 per plant, respectively), the leaf area index (LAI) was the lowest (6.3, 9.2, 10.8 and 13.4 respectively). The efficiency per plant was reduced for both the dry matter and grain production as the PPD increased. The increase of production of both the dry matter and grain per area as PPD increased was due to the photosynthetic process and the large LAI. CONCLUSION. It is possible to increase common bean yield by increasing the plant population density if water and fertility are not problems.