Black pleural effusions (BPE) are rare, exudative pleural effusions that produce a black fluid on thoracentesis. While the name and definition of this pathology is undeniably simple, the etiologies, outcomes, and treatments for BPE are incredibly complex. Currently, BPE is not well-demonstrated in the literature. This case series reports three patients with different etiologies, past medical histories, presenting symptoms, treatments, and outcomes. BPE caused by pancreatic-pleural fistula and opportunistic infections are demonstrated in this case series. This report shows that early identification and treatment of the underlying cause of BPE is critical to the recovery of the patients.