Aims: Sponges harbour diverse prokaryotic and eukaryotic microbes. However, diversity of sponge-derived Actinomycetes is of high interest because of its bioactive compounds. In the present study, diversity of Streptomycetes associated with marine sponges collected from Pongibalu (south Andaman) was investigated. Methodology and results: Sponges samples were collected by underwater SCUBA diver and Kuster’s agar media was used for isolation of actinobacteria. Colony morphology and 16s rRNA were studied for identification of isolates and phylogenetic tree was constructed using MEGA.6. A total of ten Streptomyces species were identified based on 16S rRNA gene sequencing from three sponge species (Hemiasterella spp. Tentorium spp. and Tethyopsis spp.). The organic extracts of these ten isolates revealed bioactivity against tow Gram positive and eight Gram negative pathogenic bacteria. Conclusion, significance and impact of study: This study suggests prospects and potentials of the diverse population of Streptomyces with bioactivity in marine sponges. It would be a potential source in the pharmaceutical industries. As well as actinobacteria associated with sponge may prevent the sponge from pathogenic bacteria, fungi, virus and other microflora by secretion of secondary metabolites on surface and inside. To understand the sponge and actinobacteria association and its bioactivity, a profound study need to be conducted.