Objectives: This pilot study aimed to explore the effects of playing tennis on cognitive functions and the effects of hand dominance on cognitive performance in tennis players. Materials and Methods: Tennis players and sedentary controls participated in the study (n=24/24). Groups were divided into two based on their hand dominance, and right-handed and left-handed participants were equally distributed (for each group n=12/12). Hand preference test, exercise background and daily life questionnaires were used for matching handedness, age, education, and sporting levels. Cognitive performance was evaluated with the verbal fluency test, Corsi’s block-tapping test (CBTT) and mental rotation test (MRT). MRT was performed bimanually, whereas CBTT was applied separately with right and left hands. Thus, we tried to determine the test that better reflected the hand effect. Results: Left-hand scores of CBTT were significantly higher in tennis players than in the sedentary controls (p=0.02). For gender difference exhibited for CBTT left-hand scores, women were more responsive to exercise effect (p=0.029). No significant difference was found based on hand preference in both groups on the cognitive tests. Conclusion: Tennis is an open skill sport that requires adaptation for continuously changing conditions and goal-directed behaviors. This can improve visuospatial skills and higher scores of tennis players in the left-handed visuospatial task may be associated with this. Besides, the widespread organization of the right hemisphere is an advantage for spatial abilities. Thus, it may create a technical advantage for left-handed tennis players. CBTT could be more indicative than the MRT for visuospatial functions.