Telomeres of most eucaryotes terminate in long stretches of short, guanine-rich repeats. Telomerase, a specialized enzyme with reverse transcriptase-like activity, has been shown to synthesize these repeats in many lower eucaryotes and several animal species. Although a sequence (TTTAGGG)n that matches the eucaryotic consensus sequence Tx(A)Gy is present in several plant species, the activity and expression patterns of plant telomerase have not been reported. Here we document the presence of telomerase activity in plant tissues using a modification of the human Telomeric Repeat Amplification Protocol (TRAP) assay. Telomerase activity was detected in barley embryo, anther and carpel tissues and in immature seeds of Arabidopsis thaliana, but not in barley leaf tissue.