3p deletions and telomerase reactivation are two of the most frequent events described in relation to non-small-cell lung cancer (NSCLC) pathogenesis. Moreover, a number of genes that map on 3p have been proposed as candidates to tumour-suppressor genes of importance in the lung cancer process. In this work, we analysed deletions at different 3p loci in relationship to telomerase activity in 66 NSCLCs obtained from patients who had suffered potentially curative surgery. Also, we evaluated prognostic implications. DNA samples were analysed for 3p deletions using five different polymorphic human dinucleotide repeat DNA markers (D3S1619 at 3p22.2, D3S3623 at 3p22.1, D3S1260 at 3p21.33, D3S3697 at 3p14.3, and D3S3722 at 3p21.2). Telomerase activity was investigated by a TRAP-based method. Possible correlations between the different molecular markers and distributions of disease-free survival were estimated. Our data revealed a significant correlation between telomerase activity and losses of heterozygosity (LOH) on D3S3697 (P=0.040), since all of the tumours showing deletion at this locus were positives for telomerase. Moreover, our results revealed clear associations with poor prognosis of patients, in the case of LOH at D3S1260 and D3S3697 (P=0.005 and 0.005, respectively). According to our data, potential repressors for telomerase may be located in chromosome 3p.