Background: Sympathetic hyperactivity and poor sleep quality have been reported in patients with myocardial infarction (MI). Sleep is an important modulator of cardiovascular function. We aimed to evaluate the effects of renal denervation (RDN) on cardiac autonomic activity and disordered sleep patterns in rats with MI. Methods: Wireless transmission of polysomnographic recordings was performed in sham and left coronary artery (LCA) ligation male rats during normal daytime sleep before and after RDN. Spectral analyses of electroencephalogram and electromyogram (EMG) recordings were performed to define active waking, quiet sleep, and paradoxical sleep. Cardiac autonomic activity was measured by analyzing the power spectrum of heart rate variability. Central sleep apnea events were measured by analyzing the EMG recordings of the diaphragm. Results: In the LCA ligation group, there was a higher low-frequency (LF)/high-frequency (HF) power ratio during sleep; the LF/HF ratio decreased significantly in the rats that underwent RDN in all sleep stages when compared with that in the rats that did not. The frequency of sleep interruptions increased without RDN in the LCA ligation group when compared with that in the sham group. This change was ameliorated and prevented with RDN in the LCA ligation group. Conclusions: Our results demonstrate significant sleep fragmentation with sympathetic hyperactivity after MI and that RDN prevents autonomic dysfunction and disordered sleep. RDN may then reduce sleep apnea and sleep-related sudden cardiac death after MI by restoring autonomic homeostasis.