One of the important issue in Gravity and Magnetic prospecting is to separate regional and residual anomalies. Determination of this separation between them is also crucial. Markov Random Fields (MRF) method is used to distinguish these anomalies. The most important property of this method is to make use of stochastic characteristic in neighborhood and 2D view. MRF does not need any training be fore use. This method is first applied to magnetic anomaly map consisting of prisms. After application, MRF method gives satisfactory results. We use Iskenderun Gulf magnetic anomaly map to determined off-shore fault lines. According to our results, we reveal fault lines along Iskenderun Gulf.