A new family of modified ZBLAN glass compositions has been synthesized which provides better stability against crystallization. A preliminary study of the Hruby factor HR shows higher values as compared to a ZBLAN glass prepared under the same conditions, utilizing similar high purity starting materials. Large rods of clear glass with a 1.5 cm diameter and up to 17 cm in length were easily obtained. Results will be presented on the physical properties and crystallization behavior of these high stability glasses.