Acute toxicity of an acaricide (Nuvan^® 1000 EC) in lizards (Agama agama) was observed within 2 minutes spraying of the acaricide in an enclosed dog kennel; heavily infested by ticks in urban area of Ibadan city, South western Nigeria. The acaricide was used at the 0.5% concentration recommended by the manufacturer (Novartis). A lizard which emerged from the kennel during the acaricide spraying exhibited acute signs of toxicity which consisted of shivering, gasping and death. The clinical signs of the acute toxicity manifested in the affected lizard resembled central nervous system (CNS) breakdown or neurotoxicity. Also, two lizards (one female and one male) were found dead in the kennel in the second and third days after the single acaricide spraying operation. The acute acaricide toxicity in lizards observed in this study portrayed the danger of environmental hazard to non-target commensal organisms and it is the first reported case in the area.