The thought of an armed attack on Sweden was for a long period of time deemed unlikely and the defense planning in Sweden has since the middle of the 20th century been characterized by dismantlement. However, recent changes in Europe and especially Russia's aggression towards Ukraine, has made Sweden rethink its policies on military defense. This has led to a political will to strengthen Sweden’s military defense and has by, among other things, led to a political decision to re-establish military organizational units in several Swedish municipalities. This study examines the effects military re-establishment has on spatial planning in two municipalities, Arvidsjaur and Sollefteå. The studied municipalities are two regions where the previous experience of military presence differs. The study showed, through interviews and studying of existing planning documents, that the previous military presence in both cases worked in favor of the municipal planning of the re-establishment. It helped the municipalities prepare for what the re-establishment means in terms of spatial needs and to minimize land use conflicts. Furthermore, it showed that the re-establishment and development of military interests will most likely affect the municipalities’ future development plans and could possibly lead to conflicts with public interests. The study also showed that there are differences and similarities in how the re-establishments affect municipal planning and that good communication is helpful in identifying and to minimize future planning conflicts between municipal development and military interests.