DissertationCommon bean (Phaseolus vulgaris L.) is the most important grain legume serving as a key source of protein and vital micronutrients for human beings worldwide. In Tanzania common bean yield average is 1 metric tons (MT) per hectare while the potential yield is reported to be 1.5 to 3 MT per hectare. The low yield among other factors is largely contributed by occurrence of foliar diseases caused by fungi, viruses, and bacteria. In this context, breeding common beans for multiple disease resistance in adapted genotypes is proposed as the most economical and environmentally safe approach for control of these diseases. Experiments were conducted on seventeen common bean genotypes for evaluation of resistance to four major foliar diseases viz., angular leaf spot, common mosaic virus disease, common bacterial blight, and anthracnose under natural infection. Phenotypic evaluation was conducted at Tanzania Agriculture Research Institute – Selian center (TARI–Selian) during the main bean growing season (March to July 2020). Experiment was laid in a randomized complete block design (RCBD) with three replications. Data were collected six weeks after planting and then after every fourteen days, three times by using the CIAT 1-9 disease rating scale. The mean disease scores were analyzed using GenStat software 15 th version. Polymerase chain reaction (PCR) was performed using four gene specific primers to screen for specific disease resistant genes. Phenotypic results showed significant variation in disease reaction and yield (P< 0.001). Genotype Mex 54 had the highest yield (2888.89kg/ha) while improved genotype S-3 recorded the lowest yield (280.44kg/ha). Molecular results indicated that 17.4% of the genotypes contained all four genes while 7.9% lacked any gene for disease resistance. Positive correlation between disease severity scores and molecular marker scores were observed (r = 0.106; P < 0.05). This suggests that genotypes confirmed as resistant for both phenotypic and molecular evaluations can be recommended as promising materials for advancement and release as resistant common bean varieties for use by farmers in Tanzania.