Background The ability to perform extended apnea depends mainly on 3 factors: a) the total body gas storage capacity (in blood, tissues and lungs), b) the tolerable levels of hypoxia and hypercapnia, and c) the ability to restrict metabolism (work economy and diving response). To maximize lung volume is an obvious way to increase a), and large lungs with small residual volume are also beneficial for reaching great depths without risking squeeze. Negative effects of large lung volume may be increased surface buoyancy and high intra-thoracic pressure, with a negative effect on venous return, risk of syncope, and a decreased diving response, which is important for c). However, trained divers have previously been reported to have large lungs (Carey et al 1956) and the positive effects may outweigh the disadvantages. The present study evaluated if large lungs are associated with good results in competitive apneic diving. Methods Height, weight and vital capacity (VC), without lung packing, were recorded in 14 male apneic divers participating in the apnea world championship in Hurgada 2006. Their previous apnea training experience was 5.8(1.2) years. Individual total competition scores i.e. the accumulated points from dives of maximal depth, time and distance, were compared with lung volumes. Results Subject mean(SE) height was 184(2) cm, weight was 82(3) kg and VC was 7.3(0.3) L. Mean dive performance of these subjects was 75(4) m for constant weight deep diving, 5 min 53(39) s for static apnea (resting submersion) and 139(13) m for dynamic apnea (pool distance). A Pearson´s correlation test revealed that lung volume was positively correlated with the total competition score (r = 0.54; P<0.05). Individual height and weight were not correlated with performance. Conclusions We conclude that large lung volume may contribute to successful apnea performance in humans and that any negative effects are outweighed by benefits.