In this study, serum samples collected from sheep were examined for the presence of antibodies against Parainfluenzavirus Type-3 (PI-3) by Haemaglutination Inhibition (HI) and Serum Neutralisation (SN) tests.

Serum samples were collected from clinically healthy sheep in Spring and Autumn 1995 in Diyarbakır and Şanlıurfa.

Of the 934 sheep sera examined, 674 (72,2%) and 516 (55,2%) were determined to be positive by HI and SN respectively. Titres varied from 1:16 to 1:1024 by HI, and from 1:8,22 to 1:375,83 by SN. Seropositivity in sheep were found to be higher in Spring than Autumn season.

It was concluded that HI test was more sensitive and spesific than SN test in the serological diagnosis of PI-3 virus infection in sheep.