This paper presents an evaluation of the neutronics prediction analysis for the MARIA research reactor core conversion from high enriched uranium (HEU) to low enriched uranium (LEU) fuel. The analysis concerns the experiment which includes two Leading Test Assemblies (LTA) of low enriched fuel, working together with highly enriched assemblies during standard reactor operation.At the time of estimated analysis the core configuration of the experiment was not known and calculations assumed operation in chosen standard conditions. After the experiment the whole analysis was repeated as “follow-up” calculations. Both sets of results were compared with measurements. This comparison gave a basis of prediction for the methods’ evaluation.