Extraction behavior of trivalent europium from nitric acid with N,N,N’,N’-tetraoctyl-diglycolamine (TODGA) in different diluents was investigated. Systematic evaluation of diluent influence on the extraction behavior was performed. Sets of secondary alcohols, ketones and alkanes with increasing carbon chain from 5 to 10 carbons were used as diluents in solvent extraction experiments. Stoichiometry of extracted europium complexes formed in the organic phase was evaluated by slope analysis of the obtained distribution coefficients. Thermodynamic extraction data for extracted complex in chosen diluents were determined and the influence of diluent polarity on the extraction behavior was investigated. A significant increase in distribution coefficients of europium was observed when non-polar diluent was utilized in the experiments when compared to ketones and alcohols. Future work will be focused on the effect of extracted nitric acid into the organic phase on the extraction behavior.