The focus of contemporary warfare studies has mainly been on the art of maneuver warfare. However, research has shown that attrition could be a plausible alternative when one part is unable to achieve a decisive victory. To survey the feasibility of deterrence by attrition, this thesis will apply a theory of guerilla warfare on the asymmetrical conflict of the winter war between Finland and the Soviet Union (1939-1940), to explore if the relativity of casualties between the nations could be explained by implementing aspects of guerilla warfare. Robert Taber compiles three guerilla warfare strategists in his book The war of the flea. In this thesis, these three theories are developed and adjusted to exclude revolutionary aspects, thereby focusing on the tactical dimension of guerilla warfare. This study concludes that the finnish tactics attained many of the indicators of guerilla warfare, and that the usage of guerilla warfare had impacted the number of casualties. It is however problematic to draw any conclusion about achieving deterrence by utilizing attrition, as the potential cost of the operation and willingness to accept it is in the eyes of the opponent.