Rhinovirus-sensitive HeLa cells (HeLa "R") and human embryo lung fibroblasts (HEL) were compared for the isolation of rhinoviruses from patients with respiratory disease. In the period May 1970 to December 1974, 526 rhinoviruses were isolated from 517 patients, 32% in both cell types, 59% in HeLa "R" only, and 9% in HEL only. The annual isolations in HeLa "R" were between 1.7 and 4 times greater than in HEL cells and may have been due to changes in the sensitivity of the cells or the prevalence of serotypes favoring the HeLa "R" cells. Acid lability was more easily demonstrated in HeLa "R" than in HEL cells, because the infectivity titers obtained were 10- to 100-fold higher.