Objective: To detect the effects of Tai Chi Chuan practice on the cognition of elderly subjects with Mild Cognitive Impairment. Methods: This is a pilot study with 26 elderly patients (mean age of 74 years) with Mild Cognitive Impairment. The evaluation instruments were Subjective Memory Complaint Scale (SMC), Rivermead Behavioral Memory Test (RBMT) and Digit Span Forward and Backward (DSF and DSB) from the Wechsler Adult Intelligence Scale (WAIS). One group of 13 patients received two weekly 60-minute classes of Tai Chi Chuan (Yang style) for 6 consecutive months, and the rest formed the Control Group. The Tai Chi Chuan Group was also evaluated as to learning of the Tai Chi Chuan practical exercises by means of a Specific Learning Test applied after three months of intervention. Results: After six months of intervention, the TCC Group showed significant improvement on the RBMT and the SMC (p = 0.007 and p = 0.023, respectively). The Control Group showed no significant differences in the cognitive tests during the study. There was a significant correlation between the Tai Chi Chuan Learning Test and RBMT (p = 0.008), showing that patients with a better performance in exercising TCC also showed a better performance in memory. Conclusions: In this study, a six-month program of Tai Chi Chuan afforded a significant improvement of the performance of memory complaints in the elderly with Mild Cognitive Impairment. Additional randomized studies with larger samples and more prolonged follow-up are needed to confirm these benefits.