Aims To assess the compatibility of alternative phytosanitary products (APPs) with the entomopathogenic fungus Beauveria bassiana (Bals.) Vuillemin. Methods and Results The APPs used were Baicao, Orobor((R)), Topneem, Rotenat and Compostonat at concentrations recommended by the manufacturers (CR), and then half (1/2CR) and double (2CR). To evaluate the compatibility, the following parameters were analysed: germination, colony forming units (CFUs), vegetative growth and conidia production. Compatibility was assessed using rates of toxicity and biological index. The association of APPs and B. bassiana was also evaluated for pathogenicity against larvae of third instar Anagasta kuehniella Zeller (Lepidoptera: Pyralidae) (1 center dot 0 x 10(8) conidia per ml). The germination of conidia of B. bassiana was reduced only by the product Orobor((R)). The CFUs were not affected by any products. The colony diameter was reduced when in contact with the products Baicao and Orobor((R)). For conidia production per colony, all products reduced this parameter. None of the products affected the pathogenicity of the fungus on A. kuehniella. Conclusions All APPs tested are compatible with B. bassiana. Significance and Impact of the Study The natural products tested and used in the field are considered compatible with B. bassiana under laboratory conditions, making possible new studies and the use of these in insect control.