Basaltic lava flows have been traditionally classified according to their surface morphology and style of emplacement (e.g., Dutton, 1884; Macdonald 1953; Wentworth and Macdonald, 1953). However, in drill core, it can be difficult to observe those distinguishing characteristics. The main objective of this paper is to present a flow chart to systematically determine the lava flow type based only on macroscopic observations that can be made in drill core. The technique presented here also assigns a level of certainty to the determination. In cases when a unique lava type cannot be determined, the technique is still able to rule out some lava types. This procedure has wide potential application and with minimal modification can be applied to any cross-sectional view of a lava flow.