This book contains five chapters. The first chapter is an introduction. Chapter two literature review, it contains review about soil types in Sudan, legumes; groundnut, Rhizobium bacteria. Chapter three materials and methods, in this study three bacterial strains were isolated from three regions in Sudan, El-Gadarif, El-Gezira and El-Obied, the parameters studied were antibiotics sensitivity of the isolates, tube and pot experiments, effect of temperature, pH and salt, biochemical analyses and molecular characterization tests were done. Chapter four is results and discussion, the study showed...