In a very closed and overcrowding environment, influenza transmission during Hajj season is almost inevitable. The aim of this study was to determine the association between pre-morbid conditions and influenza-like illness (ILI) amongst Hajj pilgrims. A cross-sectional study was conducted amongst Malaysian Hajj pilgrims in year 2007. Survey forms were distributed at Madinatul-Hujjaj, Jeddah and Tabung Haji Clinic, Medina, Saudi Arabia where pilgrims stay on transit before returning to Malaysia. Allergic rhinitis was significantly associated with sore throat (p=0.047), longer duration of cough (p= 0.017) and runny nose (p=0.016). Pilgrims who suffered from chronic obstructive pulmonary diseases (COPD) had significant association with longer duration of cough (p=0.041) and those with diabetes mellitus had significant association with longer duration of sore throat (p=0.048). Underlying asthma was significantly associated with severe influenza like illness requiring admission to hospital for further treatment of respiratory symptoms (p=0.016). Based on these findings, we suggest those with underlying asthma should be discouraged from participating in the hajj and they should seek early treatment if they develop respiratory symptoms.