In an iron-depleted broth culture of cowpea Rhizobium (a peanut isolate), phenolate type of compounds were detected. Chemical characterization showed the presence of 2,3-dihydroxy benzoic acid (DHBA) and 3,4-DHBA in the siderophore extract. Lysine and alanine were identified as conjugated amino acids of the siderophore. Maximum concentration of the siderophore in the culture supernatant was found after 24 h of growth. The compounds in the extracted siderophore induced growth of Rhizobium in a medium containing EDTA. Addition of lysine and alanine in the growth medium (20 mM each) led to a fourfold increase in siderophore production.