The incident happened around 1:30 a.m. Friday along the 1100 block of E Cheltenham Avenue.
Police say a 49-year-old woman sustained a stab wound to the neck. A 50-year-old man was stabbed in the chest. Both are hospitalized in stable condition.
The family member who allegedly stabbed the two victims is now in police custody.
There is no word on what led to the dispute.