Four undigested and four anaerobically digested sewage sludge samples were analyzed for enteroviruses and hepatitis A virus using seminested and double polymerase chain reaction (PCR), respectively. For enteroviruses, all eight samples were positive when detection was by seminested PCR. Using cell culture all samples except two digested sludge samples were positive. For hepatitis A virus, seven out of eight samples were positive by PCR detection. In all samples, PCR inhibitory substances were removed by passage through Sephadex G-50 and Chelex 100 columns. Overall the PCR methodology was highly successful in identifying the presence of both viruses; however, with this methodology, there was no indication as to whether enteroviruses or hepatitis A viruses not confirmed in cell culture were infectious.