Lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), adults were collected from six eastern Texas broiler facilities and examined for susceptibility to four formulated insecticides. Data indicate that A. diaperinus adults exposed to filter papers treated with the label rates of the insecticides exhibit some level of recovery. Approximately 20% or less A. diaperinus adults treated with Tempo SC Ultra (8 ml/92.9 m², 11.8% β-cyfluthrin) or Talstar WP Insecticide/Miticide (23.3 ml/92.9 m², 10% bifenthrin) and recorded as moribund at the 4-h observation period recovered by the 24-h observation period. A. diaperinus adults treated with Tempo SC Ultra and Talstar WP also had the greatest percentage of mortality for both observation periods. A. diaperinus adults treated with Dragnet SFR (49.7 ml/92.9 m², 36.8% permethrin) had the greatest level of recovery at ≈50–60% overall, which was similar to that recorded for the water-only control. Additionally, five of the six A. diaperinus populations treated with Dragnet SFR resulted in <10% mortality for both observation periods. Unlike the other insecticides examined, Talstar Professional Insecticide (10 ml/92.9 m², “Talstar Pro,” 7.9% bifenthrin) resulted in ≈50% more A. diaperinus mortality at the 24-h than the 4-h observation period due primarily to increased mortality recorded for Farm F. A. diaperinus adults from farm D had ≥87% knockdown 4 h after treatment to all compounds examined, indicating a high degree of sensitivity to these compounds. However, ≈90% of the A. diaperinus adults from this population treated with Dragnet SFR and recorded as moribund recovered by the 24-h observation. A. diaperinus adults from this population treated with the other insecticides exhibited limited recovery. Susceptible adult A. diaperinus populations are still present in Texas, based on the populations examined. But, identifying these populations is difficult and time-consuming. Consequently, screening populations before treatment might not be feasible. However, newer generation pyrethroids examined in this study seem to be suitable for suppressing A. diaperinus populations in broiler facilities.