Postmastectomy pain syndrome poses a significant treatment challenge. We present the case of a 42-year-old woman who presented to our pain clinic with a 16-month history of postmastectomy pain. We performed a combined superficial and deep serratus plane block using bupivacaine, dexamethasone, and clonidine. At 1-month follow-up, the patient had 100% pain relief. At 2-month follow-up, her pain was 5/10. The block was repeated with the same drugs at 3 months with similar pain relief. This case illustrates the utility of a combined superficial and deep serratus plane block in postmastectomy pain syndrome with a possible benefit from added dexamethasone and clonidine.