Rapid, detailed, and accurate analysis of the length spectrum of 3′ terminal poly(A) in an RNA population can be obtained by 3′-terminal 32P-labelllng of RNA with T4 RNA ligase, digestion with ribonucleases T1 and A, and use of gel sequencing methods. Length distributions of 3′-terminal poly(A) of EMC virus, poliovirus, rhinovirus, RAV-61, and CPMV virion RNAs as well as mouse globin mRNA are presented. © 1979 Information Retrieval Limited.