This paper develops comparative statics of the optimal charitable contribution to an impure public good, assuming uncertainty about the extent to which the good is private or public. This paper also examines the effect of an increase in risk aversion on an individual’s own charitable contribution. We show that the comparative statics effects of changes in distribution function on an individual’s own charitable contributions can be expressed in terms of the magnitude or monotonicity of the (endogenous) absolute risk aversion index given the normality of consumption.