The development of spider mite populations (T urticae and T cinnabarinus) as well as plant injuries on different croton cultivars were studied. Observations were conducted in commercial and experimental glasshouse conditions. The highest spider mite populations were noticed on cultivars Norma and Petra, the lowest on Golden Sun. Tetranychus urticae was the dominant species in commercial glasshouses. Croton cv. Norma was severely injured by T urticae. The leaf damage index (LOI) for this cultivar was almost 4 after sixteen weeks of mite infestation.