The analysis involved 1,258 armed robbery cases reported to the Montreal and Quebec City police forces during 1979 and 1980 (in the case of Quebec City) and 1980 only in Montreal. The sample was taken at random, and the proportions retained were different depending on whether the robberies were solved. The study selected 705 solved cases and 561 unsolved cases. Types of armed robberies were identified by the key variables of the targets and the number of suspects. First, 10 types of criminal methods were established and studies comparatively in terms of the following descriptive variables: the nature of the robbery (with a firearm or other means), the amount robbed, the suspects' ages, the use of a disguise and the nature thereof, the use of violence, the attitudes of the witnesses and victims, the number of witnesses, the use of a vehicle, and observing the robbers' means of escape. Based on this analysis, six types of criminal methods sufficiently different from one another were identified. These indicate different levels of planning and organization. The rates of solution as well as the time of arrest (period of time after the offense) varied by method of operation. A surprising finding was that the types of robberies where the levels of planning and organization appear to be the lowest (individually owned businesses, convenience stores, and robbery of persons) are also the ones where the solution rate is low; while robberies committed by groups against financial institutions are both the best prepared and the most often solved. Tabular data and four references are provided.