Background: Moraxella catarrhalis, is one of the causative organisms of respiratory tract infection (RTI) of human. It colonizes the respiratory tract (RT) and causes infections including pneumonia otitis media, sinusitis and bronchitis due to its ease of transmission by air droplets from infected or carrier people. Objective: determination of the prevalence of M. catarrhalis as potentially pathogenic bacteria (PPB) in the respiratory tract, among Umrah visitors and pilgrims from different ethnic groups. Methodology: This study was carried out on 1592; 979/613 Umrah visitors / Pilgrims from different nationalities, in the period from Rabi-Al-Awwal to end of Zo-Alhejja 1430H. Results: Moraxella catarrhalis was isolated from 109 (11.1%) Umrah visitors before performing Umrah and 217 (22.2%) Umrah visitors after performing Umrah and isolated from 59 (9.6%) pilgrims before performing Hajj and 121 (19.7%) pilgrims after performing Hajj. Conclusion: The current study showed that Mass gatherings during Hajj and Umrah seasons helps to increase the spread of M. catarrhalis infection from both symptomatic patients and asymptomatic carriers.