G1 (1-[5-bromofur-2-il]-2-bromo-2-nitroethene) is a novel antimicrobial compound developed in Cuba with reported broadspectrum activity against Gram-positive and -negative bacteria, yeasts and fungi. A compound of this nature may have considerable therapeutic potential. We tested the in vitro activity of this novel compound against 3595 organisms using microbroth dilution. The following are MIC50, MIC90 and range respectively for some of the microorganisms tested: E. coli 16, 16, 4 32; Klebsiella sp. 16, 16, 8 32; Citrobacter sp. 16, 16, 8 16; Enterobacter sp. 16, 16, 8-16; Proteus sp. 16, 16, 8-16; Coagulase-negative staphylococci 16, 32, 4-32; Enterococcus sp. 16, 32, 2-32; Staphylococcus aureus 8, 16, 4-16; Streptococcus agalactiae 4, 8, 4 8; Streptococcus pyogenes 4, 8, 0.25-16; Candida albicans 2, 2, 1-4; Candida tropicalis 4, 4, 2-4; Candida sp. 2,4, 1-4. MIC values appear lower for Gram-positive microorganisms and yeasts. G1 appears to be a novel antimicrobial agent with broad spectrum activity against bacterial and fungal pathogens. Defining the activity of this compound against multi-resistant bacteria is a priority.