Conjunction of Multizone Infiltration Specialists (COMIS) is a model that can be used to simulate air flow and pollutant patterns in a multizone structure. Experimental data from air flow measurements in single sided naturally ventilated spaces, common in urban environments, and from cross-ventilated spaces, are compared against predictions from COMIS. The single sided ventilation experiments were performed in a full scale building and a test cell, which led to the definition of a correction factor for COMIS. Cross-ventilation experiments were performed in two zones of a full scale building. Results from both experimental and calculated data using COMIS were in good agreement.