Herbal medicine represents one of the most important fields of traditional medicine all over the world. To promote the proper use of herbal medicine and to determine their potential as source for new drugs it is essential to study medicinal plants .The present investigation was undertaken to evaluate the antimicrobial activity of crude extract isolated from callus and different plant parts (leaf, stem and root) of a medicinal plant - Clerodendrum inerme. In vivo and in vitro antimicrobial efficacy of various extracts of Clerodendrum inerme was assessed by disc diffusion method against Gram positive bacteria - Bacillus subtilis (ATCC 6633) (B.s.), Staphylococcus aureus (ATCC 25923) (S.a.) Gram negative bacteria - Escherichia coli (ATCC 25922) (E.c.), Psedomaonas aeruginosa (ATCC 27853) (P.a.) and fungal strains Aspergillus niger (ATCC 16404) (A.n.), Aspergillus flavus (ATCC 9807) (A.f.), Candida albicans (ATCC 5027) (C.a.) and Candida glabrata (ATCC 66032) (C.g.)on the basis of inhibition zone and minimum inhibitory concentration.  The crude extract of selected plant parts and callus with methanol showed significant and more pronounced antimicrobial activity on the used microorganisms.