We describe a patient who is a carrier of hemophilia B, who was unusual in that she had symptoms and abnormal hematologic findings. She became pregnant and desired to have chorionic villus sampling for fetal sex determination. This was performed without complication. Her pregnancy continued, and she was delivered of a normal female infant with no complications for mother or infant. We believe this to be the first report of chorionic villus sampling in a symptomatic carrier of hemophilia B.