In this study, we analyzed the stability of the Korean regional housing market βs before and after the Global Sub-prime Mortgage crisis. The results from our analyses are as follows. First, the mean and the standard deviation of the Korean apartment return vary from region to region. Before and after the crisis, both the means and the standard deviations decrease in the capital area, while they increase in other regions. Second, almost all regions’ βs are statistically significant during the observed period. However, fewer regions’ βs are significant before the crisis than after the crisis. This shows that the market efficiency increases after the sub-prime mortgage crisis and that factors other than market return can affect apartment return in local regions. Third, most regions show significant differences in β between before and after the period. After the sub-prime mortgage crisis, the systematic risk of the capital regions decreases while that of other regions increases. Fourth, there exists the risk-return relationship both before and after the sub-prime mortgage crisis. However, the effect of β on return was greater after the period than before.