In designing single sampling inspection plans, a problem is to find the acceptance number, $c$, and the smallest sample size, $n$, such that if the fraction defective of the material inspected is equal to an acceptable value, $p_1$, a large percentage, say, 95% of such lots will be accepted under the sample criteria, whereas if the fraction defective of the material inspected is objectionable and equal to $p_2$ (where $p_1 < p_2$), then a large percentage, say, 90% of such lots will be rejected. A solution to this problem for the case where the lot size is large compared to the sample size is given in this paper and tables are provided for quick determination of the sample size $n$ and acceptance number $c$.