Abstract: The antifungal and cancer cell growth inhibitory activities of 1-(3?,4?,5?-trimethoxyphenyl)-2-nitro-ethylene (TMPN) were examined. TMPN was fungicidal for the majority of 132 reference strains and clinical isolates tested, including those resistant to fluconazole, ketoconazole, amphotericin B or flucytosine. Minimum fungicidal concentration/minimum inhibitory concentration (MFC/MIC) ratios were ?2 for 96% of Cryptococcus neoformans clinical isolates and 71% of Candida albicans clinical isolates. TMPN was fungicidal for a variety of other basidiomycetes, endomycetes and hyphomycetes, and its activity was unaffected by alterations in media pH. TMPN was slightly cytotoxic for murine and human cancer cell lines (GI50=1-4 ?g/ml), and weakly inhibited mammalian tubulin polymerization (IC50=0.60 ?g/ml). TMPN may also be used as a biochemical probe for tubulin and fungal dimorphism studies.