This study was conducted for identification and introduce of Tintinnida order in Iranian waters of Oman Sea from Hormuz Strait to Pasabandar, Chabahar, in 2007. Ten transects each with four fixed stations had been chosen. Samplings were conducted in two seasons before and after monsoon. Depth of sampled stations in the studied area varied from zero to 20m and 20 to 50m and in station one because oflow depth (5m) sampling carried out just one time.

We identified a total of 16 genera of Tintinnida from ten families. These composed of 4 genera belonging to family Tintinnidae, 2 genera from family Xystonellidae, Ptychocylidae and Rhabdonellidae. Familes Tintinnidiidae, Codonellidae, Epiplocylididae, Dictyocystidae, Metacylididae and Ascampbeliellidae were each represented by only one genus. Tintinnopsis from Codonellidae was the most abundant composing 54% of the samples and Epiplocyloides from Epiplocylididae with 0.01% was the least abundant.

The most frequent genera of Tintinnidae included: Eutintinnus, Amphorellopsis, Salpingella and

Dadayiella.