We have developed a method for constructing genomic libraries enriched for telomeric DNA sequences, enabling the isolation of telomeres from higher eukaryotic organisms with large chromosomes. The method was used to clone telomeric DNA sequences from the flowering plant Arabidopsis thaliana. A. thaliana telomeres are composed primarily of tandemly repeated blocks of the sequence 5'-CCCTAAA-3' and are heterogeneous in size. Genomic sequences that cross-hybridize at high stringency with A. thaliana telomeric repeats are present in other higher plants. In Zea mays (corn), these cross-hybridizing sequences are located at the telomeres. In addition, the A. thaliana telomeric repeats cross-hybridize at low stringency to genomic sequences located at the telomeres of human chromosomes.