In the finance literature determinants of Capital structure have been widely debated. Previous studies have mainly focused on microeconomic determinants in countries outside Sweden and research on the Swedish market has been sparse. This study aims to analyze how microeconomic determinants such as profitability, firm size and tangible assets affect the capital structure and further how the determinants from the Swedish macroenvironment like inflation, tax rate and interest rate affect capital structure. The study considers previous theories on capital structures relevance and evaluates the Swedish firms support for the Irrelevance Theory, Pecking order and the Trade-off theory. In other words, by evaluating how the determinants affect the capital structure we were able to see connections between theory and how Swedish firms determine their financing decision.  Based on a review of the literature and theories, the determinants, the quantitative approach,  and collection method was decided. The data was collected over a 10-year period between  2010 - 2019 and amounted to 1116 firms and 44 632 observations. A multiple regression  method was performed where the dependent variable the debt ratio was split into short-term,  long-term, and total debt to get a better understanding of the results.  Analysis of the results demonstrated that Swedish firms' total debt ratio had a significant negative relation towards profitability. This indicates that Swedish firms choose to finance their operation with internal funds rather than with debt which supports the Pecking order Theory. However, the determinant growth show significant negative relationship to the  debt ratio which is in support for the Trade-off theory. The results imply Swedish firms conflicting support for theories on capital structure. Our results from a change in the  Swedish macroenvironment show that inflation causes firms long-term debt ratio to  decrease, which potentially demonstrates the fear of higher interest rates as inflation hits  and an unwillingness to finance with debt when the cost of financial distress increases.   Considering previous studies has shown contrasting results on the determinants effect on capital structure. We consider our findings to be in line with overall expectations and believe we add further knowledge which can be applied to the Swedish business environment.