Human parainfluenza viruses (HPIVs) are distributed worldwide and are involved mainly in the pathogenesis of respiratory tract infections. The development and optimization of three quantitative reverse transcription real time polymerase chain reactions (RT Real Time Qt-PCRs) and an indirect immunofluorescence (IFA) for the detection and quantitation of HPIV-1, -2 and -3 in clinical samples are described. Efficiency, sensitivity, specificity, inter- and intra-assay variability and turnaround time of the two methods were compared. These assays have been validated on 131 bronchoalveolar lavage specimens. Based on the results obtained, the molecular methods represent a valid and rapid tool for clinical management and should be included in diagnostic panels aimed to evaluate suspected respiratory tract infections.