Background. Shrimps are one of the most valuable marine resources of Oman and shrimp fi sheries is greatly contributing to the national economy, and sustainability of traditional fi sheries villages. However, the shrimp trawl fi shery has one of the highest bycatch rate of any fi shery and cause negative impacts to marine populations and benthic habitats. This study provides the fi rst data on the c omposition and abundance of the bycatch in the main shrimp fi shing grounds distributed along the south-eastern coastline of Oman in the Arabian Sea. Materials and methods. Shrimp trawl survey was conducted monthly from January to December 2013 in seven sites using demersal otter trawl. Overall, 93 trawl catches were used for the analysis of the bycatch composition based on weight, number, and frequency of occurrence. Top ten species and top fi sh families, cephalopods, and crabs were defi ned in the bycatch. The bycatch compositions were compared in different regions using biodiversity indices and the cluster analysis. Results. Mean monthly bycatch during the shrimp trawling survey in the coastal waters of Oman in 2013 ranged from 22.2 to 191.5 kg · h –1 , in different months with an overall mean (±SE) of 58.7 ± 5.2 kg · h –1 (n = 93). The bycatch to catch ratio was estimated 8.9 : 1 for shrimp fi sheries. This ratio fl uctuated signifi cantly over the year with minimum values from April to September. The bycatch composition included 97 bony fi sh species from 36 families, 12 species from 7 elasmobranchs families and several species of cephalopods and crabs. Catfi shes (Ariidae), frogfi sh (Antennariidae), ponyfi shes (Leiognathidae), and rays (Dasyatidae and Gymnuridae), represented a majority of the bycatch. Conclusion. Shrimp fi shery in Oman is affecting mainly small-sized and slow-moving fi shes, and invertebrates with low economic value. However, the fi ne-meshed shrimp trawls also capture juveniles of commercial important fi shes and cause some ecological problems. The results from the study point out the necessity of management actions to develop a special policy on bycatch reduction in Oman fi sheries.