In this study of 9,12-octadecadienoic acid, some aliphatic and aromatic esters were synthesized and screened for antimicrobial activity by following tube dilution method against Gram positive bacteria: Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Gram negative bacteria: Escherichia coli, Pseudomonas aeruginosa and two fungal strain: Candida albicans and Aspergillus niger respectively. Compounds L6 (3-Nitrophenyl octadeca-9,12-dienoate) and L7 (4-Nitrophenyl octadeca-9,12-dienoate) were found to be most active compounds against bacterial strains and compound L8 (Benzyl octadeca-9,12-dienoate) emerged as most active antifungal agent among the synthesized derivatives. The structure of all the synthesized compounds was found in agreement with their spectral data.