There are given k Poisson processes with parameters (rates of occurrence) λ1, …, λk. Let λ(1)≤ λ(2)≤ … ≤ λ(k)denote the ordered set of values of the parameters. A procedure is given for selecting the process corresponding to λ(k)and estimating its parameter (λ(k)). The given procedure controls the joint risk of improper selection and of large error in the estimate. Let θ > 1 and 0 < α, β < 1 be given numbers, and let δ denote the estimate of λ(k). The joint probability that a correct selection is made and that |(δ/λ(k)) − 1| ≤ α is at least as large as β, for (λ(k)/λ(k−1)) ≥ θ. Two cases are considered, that is, when the processes are observed continuously in time, and when they are observed at successive intervals of time. Both the cases lead to the same theoretical results.