This study focuses on the current account deficit dynamics and sustainability, using data of the period between 1990:Q1 and 2014:Q2 in the context of Turkish economy. The main findings of the study can be put into two categories. The first category covers energy consumption, openness rate, gross domestic product, exchange rate and investments, which are the most important determinants of the current deficit. The second one asserts that sustainability is weak for Turkish economy; however, it is even weaker during the economic contraction. There is extensive literature about structure and sustainability of the current account deficit. However, many of the studies have analysed the sustainability of the current account deficits without considering the economic conjuncture. For this purpose, the study employs the Markov-switching method which is a non-linear time series model.