Human parainfluenza viruses (HPIVs) are an important cause of acute lower respiratory tract infections (ALRTIs). HPIV-4, a newly identified virus, has been associated with severe ALRTIs recently. A total of 771 nasopharyngeal aspirate samples were collected from hospitalized children between March 2010 and February 2011. HPIVs were detected by Nest-PCR, and other known respiratory viruses were detected by RT-PCR and PCR. All amplification products were sequenced. HPIVs were detected in 151 (19.58%) patients, of whom 28 (3.63%) were positive for HPIV-4, 12(1.55%) for HPIV-1, 4 (0.51%) for HPIV-2, and 107 (13.87%) for HPIV-3. Only three were found to be co-infected with different types of HPIVs. All HPIV-positive children were under 5 years of age, with the majority being less than 1 year. Only the detection rate of HPIV-3 had a significant statistical difference (chi(2) = 29.648, P = 0.000) between ages. HPIV-3 and HPIV-4 were detected during the summer. Sixty (39.74%) were co-infected with other respiratory viruses, and human rhinovirus (HRV) was the most common co-infecting virus. The most frequent clinical diagnosis was bronchopneumonia, and all patients had cough; some patients who were infected with HPIV-3 and HPIV-4 had polypnea and cyanosis. No significant difference was found in clinical manifestations between those who were infected with HPIV-4 and HPIV-3. Two genotypes for HPIV-4 were prevalent, although HPIV-4a dominated. HPIV-4 is an important virus for children hospitalized with ALRTIs in China. HRV was the most common co-infecting virus. Two genotypes for HPIV-4 are prevalent, HPIV-4a dominated. J. Med. Virol. 88:2085-2091, 2016. (c) 2016 Wiley Periodicals, Inc.