Bovine Parainfluenza-3 Virus (BPI-3V) is one of the most viral agents that causes respiratory diseases in beef and dairy cattle. This study is considered the first study in Iraq to evaluate some clinical and some epidemiological features of BPI-3V infection in cows and investigated the presence of the virus by using direct enzyme linked immune-sorbent assay (ELISA) and Real-Time quantitative reverse transcription polymerase chain reaction Real-Time RT-qPCR based on primers and Taq-Mam probe specific for nucleoprotein gene of BPI-3V according to National Center for Biotechnological Information NCBI in USA with product size 84 base pair. This study was carried out between November 2012 and April 2013 by examination of (147) animals that showed respiratory signs in different ages (6 months - 8 years) and sex from different regions in Al-Diwaniya province. Serological study examined ( 86) blood samples which collected from clinical cases, whereas molecular study examined (28) nasal swabs which collected from clinical cases, and (33) tracheal specimen and (33)lung tissues that collected from slaughtered animals.