The Superphenix reactor was a Sodium-cooled Fast Reactor (SFR) developed under a European framework that intended to provide a general design of a commercial power plant. During the start-up of the reactor, six different batches containing dummy assemblies allowed to verify the main safety criteria at zero-power conditions tests at 180DC. The present paper presents a stochastic analysis of two start-up cores by comparing the experimental results with the performed calculations with TRIPOLI-4 and the JEFF 3.1.1 nuclear data evaluations. The main and back-up control rod evaluations, the critical mass, as well as the handling error experiment are examined. In addition, two particular irradiation tests are studied to determine the flux distribution of the core and finally, the assessment of a subcriticality analysis is performed to verify the validity of the former MSM factors. In general, the obtained results show good agreement with the experiment, having a general reactivity bias with the performed calculations, the flux distribution is also in great agreement with the tests with small discrepancies and the MSM evaluation permitted to observe better consistency with experimental data. The obtained results allowed to validate our model and will serve as reference calculation for further research.