Theoretical, clinical, and empirical implications of the functional connections between symptoms of obsessive-compulsive disorder (OCD) and posttraumatic stress disorder (PTSD) are abundant. As such, four cases are presented here of men and women who met criteria for comorbid OCD and PTSD. All had been diagnosed with treatment-resistant OCD and were seeking treatment from an OCD specialty clinic or institute, all reported a history of traumatic experiences prior to the onset of OCD, and all appeared to demonstrate negative treatment outcomes. Upon examination, it appeared that symptoms of OCD and PTSD were connected such that decreases in OCD-specific symptoms related to increases in PTSD-specific symptoms, and increases in OCD-specific symptoms related to decreases in PTSD-specific symptoms. Speculations about the function of OCD symptoms in relation to post-traumatic psychopathology are put forth; and theoretical, research, and treatment implications are discussed.