Momentum strategies based on TSE 300 sector indices have been profitable over the 1962-2000 period, especially for six-month formation and holding horizons. The risk decreases considerably when four sectors rather than only one are considered in the extreme winner and loser portfolios. For the long-short winner-loser portfolios, the abnormal returns are slightly higher than the total returns. This is consistent with the inability of the Fama and French three risk factors to explain the profitability of momentum strategies. This result holds when the risk associated with the long-short winner-loser portfolios is considered constant or when it varies through time. Comparison of the profitability of momentum strategies based on the total past return, on the specific component and on the factor component of return shows that most of the returns observed for the sector momentum strategies are generated by the specific component of returns.