We collected fecal scat pellets from 4 black-footed ferrets (Mustela nigripes) in captivity. The ferrets were fed black-tailed prairie dogs (Cynomys ludovicianus) that had previously consumed 0.005% fipronil grain. Fipronil is an insecticide from the phenylpyrazole chemical family. Specifically, ferrets were fed portions of three prairie dogs (60-80 g/day) for one week. We collected scat from the ferrets before, during, and after their feeding on treated prairie dogs. The scat was stored in sealable plastic bags and frozen. Fecal pellets were placed in 1.5 milliliter (mL) centrifuge tubes, ground into morsels and powder (fine particles for flea larvae to eat) with a disposable polypropylene pestle, separated as 0.50 milligram (mg) subsamples into pre-labeled centrifuge tubes, and frozen. Oropsylla montana flea larvae were assayed in 12-well microplates. Small holes were made in the microplate caps, immediately above each well, to allow for air exchange. Each well contained sterilized fine sand substrate (approximately 1/4 to 1/2 of well depth) for larvae locomotion and refuge. Wells in some of the test plates received fipronil-laced ferret feces and wells in the remaining plates received ferret feces lacking fipronil residues (0.50 mg/well). The microplates were lidded, loosely covered with aluminum foil, and stored in a dark, cool storage location for 24 hours at approximately 23 °C and approximately 85% relative humidity. After 24 hours, the microplates were uncovered and opened. Probes were used to prod each larva for 2 seconds. Live larva responded by coiling and moving away from the prod. Larvae that did not respond within 2 seconds were prodded for 5 additional seconds and considered dead if no movement was observed. A 60x to 120x pocket microscope was used to determine if each larva consumed ferret feces (yes = visible meal, colored like prairie dog scat, in the gut; no = no visible meal in the gut). The data file (FerretFipronilScatFleaLarvaeData.csv) includes data on flea identification numbers (FleaNumber), treatment (Fipronil, NoFipronil in ferret scat), evidence of flea larvae consuming ferret scat (Meal, Yes or No), and a binomial variable for whether or not a larval flea survived the 24-hour testing period (Survived).