Microorganisms have attracted considerable attention as a new source for pharmaceutical agents. Several peptidic natural products synthesized by fungi and bacteria are assembled by large enzymes, referred as nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS). The products (siderophores or other bioactive peptides) formed by this biosynthetic pathway may be related or connected to functions of events of the microorganism's life cycle, such as iron scavenger. Bioprospection of microorganisms isolated from Archaeological Dark Earth soil of Brazilian Amazon is of great importance to the knowledge of this tropical biome. This study aimed to correlate the presence of siderophores produced by microorganisms isolated from ABE soil of Brazilian Amazon and the presence of genes encoding NRPS and PKS. Bacterial strains were isolated from soil samples collected at 10, 20 and 40 cm depth. A total of 143 isolates were screened for siderophore activity. The isolates were grown in specific liquid medium for 2 d at 28^oC. For siderophore analysis, bacterial strains were inoculated on plates containing an iron-limited medium (MM9) amended with a chromeazurol S-Fe₃ complex. Sixty-seven isolates showed positive reaction for siderophore production. Twenty of them were selected for further studies. Genomic DNA was extracted and PCR amplification was carried out using specific primers for NRPS (MTF/MTR) and PKS (KSF/KSR). The results showed that TP69, TP109 and TP283 isolates presented NRPS, TP104, TP106, TP108, TP110, TP285 and TP443 isolates presented PKS and only TP92 and TP101 isolates showed both genes. The presence of NRPS and PKS genes in 55% of the isolates tested suggests that production of siderophores may occur by a nonribosomal pathway. Mass spectrometry is been used to identify the compounds detected.