Abstract: The present study determined the best conditions (parameters such as initial pH of the culture medium, culture system, time and temperature of incubation) for strains of moulds of the genus Arthrinium to produce secondary metabolites with antibiotic capacity, avoiding 3-nitropropionic acid (3-NPA) production, due to its neurotoxicity. It was observed that the desirable conditions for these strains to get our aim were: initial pH of the culture medium: 5, colonies developed under static conditions, incubation at 28°C and during 14 and 21 days.