Antimicrobial and antifungal activity of some poly substituted benzene derivatives against grampositive bacteria i.e. Psydomamonas aeruginosa ATCC 29212, Bacillus subtilis RSKK 244, Bacillus megaterium clinical isolate , gram-negative bacteria Micrococcus Luteus NRRLB and as fungus Candida albicans ATCC 90028 were studied. Poly substituted benzene derivatives were 2,4,5- trichloroflourbenzene; 2,4,5-trichlorobromobenzene; 2,4,5-trichloro iodobenzene; 1,2,3,4-tetrachlorobenzene; 1,2,4,5-tetrachlorobenzene. As a result, the substituent which attached to the benzene ring, affected the antimicrobial and antifungal activity. Even substituent is same but position of substituent over the benzene ring is different activity were affected differently