ABSTRACT In Brazil, a large portion of peanut production is found under conventional soil preparation. Due to the fact that there is a lack in studies related to the cultivation of peanuts in conservationists soil preparation, mainly in the field of losses and mechanized harvesting. Thus, it was aimed to assess the quality of digging and gathering operation of peanut, based on losses, using statistical process control techniques in two tillages. The sowing was carried out under conventional and conservationist preparation, revolving only the sowing line. Losses were evaluated in the digging and gathering operation, being that in the gathering it was evaluated the harvest losses in three displacement speeds (4, 6 and 8 km h-1) in two tillages. The quality of the process was affected by the soil preparation based on the visible and invisible losses, respectively. Regarding the gathering, the conservationist preparation, it was unstable in all indicators, whereas in the conventional preparation it was noticed reduction of the variability for all the displacement speeds. The peanut sowing under conservationist preparation provided a better quality digging. In contrast, the gathering of pods in areas under conventional tillage showed a better quality of the operation.