This study was conducted to reveal the effects of bat guano on the growth, quality, content of photosynthetic pigments and nutrients of Begonia semperflorens L. under salt-free conditions, to determine the effects of salt stress on the related species, and to figure out whether there is an alleviating effect of bat guano on salt stress. For this purpose, 40 g (50 t ha^-1) bat guano per pot was used at various sodium chloride (NaCl) applications, including 0, 20, 40, 50, and 60 mM. The experiment was conducted in plastic pots with a volume of 2 L containing the peat+perlite mixture (3:1) by using a completely randomized experimental design with five replications. Bat guano had effects on all studied traits at a 0.001 probability level without Chl a/b. This study revealed that the contents of Chl a, Chl b, and the concentrations of all nutrients in leaves of B. semperflorens highly decreased at 60 mM NaCl compared to control treatments. Bat guano treatment without NaCl increased over 25% root fresh and dry weights. Bat guano was used to improve the effects of salt stress on B. semperflorens.