The toxicity of the non-steroidal ecdysteroid agonist tebufenozide was evaluated topically on adults of the cosmopolitan cockroach Blattella germanica (Blattodea: Blattellidae). The LD₅₀ value was estimated at 402 μg/g of insect (range, 95% fiducial limits: 293–552) at 15 days after treatment. The effects on reproduction were observed in adult females of cockroaches that survived exposure to a LD₂₅ (146 μg/g of insect) of tebufenozide. Dissection of treated females showed a clear reduction in both the number of oocytes per paired ovaries and the size of basal oocytes, as compared to controls. In addition, tebufenozide significantly reduced the mating success of pairs and altered the fertility as shown through the reduction of ootheca development and total absence of viable nymphs. Tebufenozide disrupted the Germancockroach reproduction by interferring with the homeostasis of the insect hormones.