The analytic and discretized dissipativity of nonlinear infinite-delay systems of the form x′(t) = g(x(t),x(qt))(q∈(0, 1), t > 0) is investigated. A sufficient condition is presented to ensure that the above nonlinear system is dissipative. It is proved the backward Euler method inherits the dissipativity of the underlying system. Numerical examples are given to confirm the theoretical results.