Oman has several accessions of cucumber but there is no information about their diversity. The aim of this study was to investigate their morphological and genetic diversity. Twenty-four accessions of Omani cucumber were collected from four regions; Sharqiya, Dakhilia, Batinah and Muscat. The experiment was conducted at Directorate General of Agriculture and Livestock Research Rumais from November 2006 to March 2007 in open field. Data on thirteen quantitative plant characteristics were recorded. In addition, sixteen qualitative characters were also recorded for the study. Shannon-Weaver diversity index analysis was used for understanding the diversity among the accessions either combined or region wise. Multivariate Analysis namely Principal Components Analysis and Cluster Analysis was employed for studying the relationship among accessions. The results of analysis of diversity index (H) for agronomic, fruit and seed characters for all regions combined or four regions individually showed that Omani cucumber accessions have high diversity (H) for characters Per se. The genetic diversity indices for the agronomic characters ranged from 0.63 for Muscat to 0.73 for Sharqiya region and the average for all regions combined was 0.73. While the indices for fruit and seed characters ranged from 0.59 for Muscat to 0.73 for Dakhilia and the average for all regions combined was 0.70. These results were confirmed with Principal Components Analysis, Cluster Analysis and Genetic Similarity clearly revealed that there were no comparable differences between the accessions in terms of morphological quantitative characters. The genetic similarity for all regions combined ranged from 0.63 to 0.92. These results suggested that the assessment of overall genetic diversity of Oman cucumber accessions indicated to be similar despite that they were collected from different regions of Oman.