Let a(n) denote any arithmetic
function. Since most arithmetic functions that are encountered are defined on only
the nonnegative integers, we define a(−n) = a(n) for each positive integer n. Our
objective is to develop a Poisson type formula for Σn=−∞∞a(n)f(n), where f
belongs to a suitable class of functions. We conclude the paper with several
applications of our arithmetic Poisson formula.