Gastric cancer (GC) is one of the major causes of death in the Colombian population. Its incidence is variable and high risk zones have been identified, among them the department of Caldas, and especially Manizales. In this pathology of complex etiology external and internal factors are found. Among the external factors are the occupational and/or environmental exhibitions to carcinogenic or procarcinogens compounds. One of them is cigarette smoke, and therefore its possible association with GC risk was explored. The new cases of GC that arose in 18 months in the Hospital de Caldas were studied. From these, 65 met the inclusion criteria and were matched with 65 controls. The information was collected emphasizing the smoking activity. Significant association was demonstrated between the smoking habit ∗ Licenciado en Biologia y Quimica, Magister en Genetica Humana. Universidad de Caldas. Universidad Autonoma de Manizales. Manizales, Colombia. E-mail: eduardo.castano@ucaldas.edu.co ∗∗ Licenciado en Biologia y Quimica, Maestria en Ciencias Economicas. Universidad Autonoma de Manizales. Universidad Nacional de Colombia. Manizales, Colombia. E-mail: hparrasa@unal.edu.co 126 Eduardo Castano Molina, Hernan Parra Sanchez and the risk to GC (OR=2,1, p=0,035). Also significant association was found between GC and the middle and low socioeconomic stratum (p=0,000). In conclusion, these results suggest that quitting smoking is a protector factor to the risk of developing GC; although there are other endogenous and exogenous risk factors that impact the presence of this type of cancer that were not explored in this