A method is provided for production of steel in a basic converter employing liquid converter slag obtained as a final slag in the previous run, where roughly half of the slag from the preceding charge is left in the converter. The basicity of the initial slag is thus considerably increased and the slag is maintained preferably over the total converting process, but at least during the critical initial stage at the saturation level with respect to magnesium oxide and dicalcium orthosilicate. At a certain level of silicon content in the pig iron the process is operated with a predetermined slag amount for each ton of steel at the end of the blowing by adding to the initial melt or respectively at the beginning of blowing a certain amount of magnesium oxide expending on the silicon content of the pig iron together with the flux charge materials. This process considerably improves the lifetime of the converter lining. In addition the amount in flux materials is considerably decreased and the slag composition is made more uniform over the run. Furthermore, the metallurgical quality of the product is improved.