In order to find some lead compounds for the treatment of opportunistic infections of malaria and pathogenic microbes, an undescribed Indonesian sponge Agelas sp. collected at Manado, Indonesian Waters, was suggested containing active compounds. Crude ethanolic extract of the sponge exhibited significant in vitro antimalarial and antimicrobial activity against Plasmodium falciparum (D6 colne) with $IC_{5O}$ values of $8;{mu}/ml$ and against pathogenic microbes such as Candida albicans $(150;{mu}/ml)$, Cryptococcus neoformans $(<20;{mu}/ml)$, Staphylococcus aureus $25;{mu}/ml$, methicillin-resistant Staphylococcus aureus $(<20;{mu}/ml)$, and Pseudomonas aeruginosa $(<20;{mu}/ml)$. Active compound (5.0 mg) was isolated from the ethanolic extracts of the sponge and purified by using silica gel and ODS column, successively. Active compound was elucidated as dibromosceptrin $(C_{22}H_{24}Br_2N_{10}O_2)$ by detailed analysis of FTESI-MS and comparison of $^1H,;^{13}C$, DEPT and HMQC NMR spectral data with those reported.