Improved lost circulation compositions that include melt-processed inorganic fibers and methods for using such compositions in subterranean formations are provided. An example of a method of the present invention is a method comprising providing a drilling mud comprising a plurality of melt-processed inorganic fibers, wherein the melt-processed inorganic fibers have a length of less than about 10 millimeters, and comprise at least one melt-processed inorganic fiber selected from the group consisting of: a basalt fiber, a wollastonite fiber, and a ceramic fiber; and circulating the drilling mud in the subterranean formation.