Driven by the growing demand for new bioactive molecules effective against multi-resistant bacteria, the research and development of new products has been propelled to the rank of the most important challenges for humanity. This present work allowed us the isolation and purification of seven strains of actinobacteria from marine water and sediment as well as the study of the inhibitory power of these isolates on some test bacteria and fungi. Antimicrobial activity was evaluated by the agar cylinder technique against two gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), two gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli), the yeast Candida albicans and two filamentous fungi Fusarium oxysporum f. sp. albidinis and Aspergillus niger. The screening of antimicrobial activities demonstrated the production of antibacterial and/or antifungal metabolites of all our isolates. The largest inhibition diameters are recorded with the S1 and E6 strain against Pseudomonas aeruginosa. The majority of isolates have an antimicrobial effect against the yeast Candida albicans with the largest zone of inhibition (18mm) noted with the E6 strain. Activity of strains S4, E5, E6 is recorded against Fusarium oxysporum f. sp. albidinis with a very large diameter of 23.5 for E6.