Pregnancy complicated by HCL is an extremlely rare event: only 5 report of HCL in pregnancy have been previously described. A 36-year-old women was diagnosed of HCL presented in 14 week of her 5th pregnancy. Therapy was initiated in 18 wk of gestation with IFN-alpha at dose 6 x 106 U subcutaneous 3 times per week and prednisone 20 mg/d. IFN-alpha administration was well tolerated. After IFN-alpha therapy partial remission was achieved. The course of the pregnancy was normal. At week 39 of gestation a cesarean cection was performed and the patient delivered a healthy male infant weighing 3460 g with Apgar score of 10. The placenta was of normal size, no infiltration of hairy cell was founded. Post-partum course was uncomplicated. The patient elected to not breast feed her infant. 3 weeks after delivery patient had a 5-days course of 2CDA