A very precise magnetospectrometric survey of Algeria was flown from 1969 to 1974 by AeroService Corporation. A new compilation of the aeromagnetic data for northern Algeria is presented. To a first order, the map shows a very good correlation between the magnetic anomaly distribution and the main geological trends. The coastal anomalies occur without a break along the foot of the continental shelf and may correspond to an opening phase of the western Mediterranean basin. The onshore magnetic anomalies exhibit a bimodal distribution, consisting of long-wavelength anomalies which may be associated with undulations of the deep basement and of short-wavelength anomalies that correspond to shallower sources that were probably created during an important Triassic volcanic event. The main trends of the two families of anomalies are geometrically well correlated.