Abstract: The objective of this study was to evaluate the effect of acibenzolar-S-methyl tested at 5 concentrations (0, 1, 5, 25 and 100 μM a.i.) for its ability to protect papaya (Carica papaya) cv. Rainbow from black spot (Asperisporium caricae) following inoculation with the fungus. Effects of resistance induction treatment against black spot disease were evaluated by measuring the plant height and stem diameter. Disease symptoms were scored weekly by visually estimating disease severity of plants on the basis of a 5-class visual scale of 0 (no symptoms) to 4 (extensive lesions on leaves). Accumulation of defence-related proteins in papaya leaves were also analysed and compared. Results revealed that the level of protection against A. caricae was dose-dependent. Maximum reduction of the disease in leaves was obtained with 25-100 μM acibenzolar-S-methyl, with a time interval of 3 days between application of the activator and inoculation with the pathogen. The systemic resistance elicitation was characterized by an increase in 2 pathogenesis-related proteins, chitinase and β-1, 3-glucanase. These results indicate that acibenzolar-S-methyl induces partial resistance in papaya against black spot disease which may provide the grower a new option for integrated management of the disease.