A Dissertation 2019Common bean (Phaseolus vulgaris L.) is the most important food legume in the world. In Tanzania the common bean crop is cultivated for home consumption as well as for cash income. The objectives of this study were to determine the effect of soil pH on levels of iron and zinc in twenty five common bean genotypes and to determine heritability of iron and zinc using the progeny of crosses between low and high micronutrients (Fe and Zn). An incubation experiment was performed in screen house to adjust soil pH to levels of 5.5, 6.5 and 7.5 using hydrated lime (Ca(OH) 2 ) for four weeks. The experimental design followed a randomized complete block design in a split plot arrangement with three replications per treatment. Two common bean seeds were sown at 5 cm in each pot and grow for three months before harvesting for analysis of iron and zinc in the laboratory. Concentration of iron and zinc in leaves and seeds were adversely affected by soil pH. The result demonstrated that soil pH can affect absorption of micronutrients directly or indirectly by affecting the nutrients availability of common beans genotypes. Hence assessing variability is fundamental to identify the most important traits in common bean improvement program. Four crosses (Nua 11 × Zawadi, Nua 11x Pesa, Nua 17 x Zawadi and Nua 17 x Pesa) using diverse parents with varied levels of grain iron and zinc concentrations were made to study heritability for iron and zinc . Broad sense heritability observed in Nua 11 x Zawadi was (56%) and Nua 11 x Pesa was (76%) for concentration of iron while Nua 17 x Zawadi was (57%) and Nua 17 x Pesa was (59%) for concentration of zinc. Narrow sense heritability observed in Nua 11 x Zawadi was (65%) and Nua 11 x Pesa was (71%) for concentration of iron while Nua 17 x Zawadi was (79%) and Nua 17 x Pesa was (63%) for concentration of iron and zinc. This study demonstrates, there were increase of concentration of iron and zinc in common bean genotypes at soil pH levels 6.5 and 5.5 that have potential for improvement of micronutrients in common beans and heritability of zinc and iron are moderate to high indicating that these traits can be improved by breeders.