Introduction: Cancer larynx is the second most common respiratory cancer after lung cancer with predominance among males due to prevalence of smoking among men.
Objective: To evaluate ABO grouping as a risk factor for cancer larynx.
Patients and methods:  Two groups, a patient group that enrolled 200 patients with cancer larynx based on clinical, radiological, and pathological assessment and a control group included 600 healthy persons. Data were collected by personal interviews and from the patient's records and from the control group. These data included: Age, Sex, Residence, Occupation, Smoking, any risk factor for cancer larynx as (GERD, alcohol consumption and spicy food), ABO grouping and RH typing (some from the records and some were done), presence of other diseases and Smoking status.
Results: Showed that the most frequent blood group in patients with cancer larynx was O positive (37.5%) while the most frequent blood group in the control group was A positive (31%).     Blood group O positive (Odd's ratio= 1.36, 95% CI= 1.09- 3.11; P= 0.01).
Conclusions: laryngeal cancer was found to be more among patients with blood group O+ve which is statistically significant (P-Value = 0.01). So, the blood group (O +ve) is a risk factor for developing cancer larynx.