Views expressed in this article are those of the author and do not reflect the official policy or position of the Department of the Navy, Department of Defense, or U.S. Government. The only previously published case of anti-G in a pregnant woman indicated that anti-G alone caused little, if any, fetal or neonatal hemolysis. This report describes an affected fetus with amnionitic fluid OD 450 absorbance values in the moderate zone of the Liley prediction graph who required prolonged phototherapy after birth until day of life 20. Anti-G was identified and anti-C and -D excluded in the mother's serum. In contrast to the previous report, this report shows anti-G alone can cause moderate HDN and that fetal monitoring and treatment may be necessary.