Ascariasis is very common in indigenous chicken causing retarded growth, low productivity and mortality. Considering the problem of Ascaridia galli in chickens, anthelmintic resistance, high cost and human health hazard of chemical anthelmintic the use of medicinal plant is an alternative choice. The study was conducted to determine the incidence of ascariasis in Polashbari upazilla of Gobindhaganj district during July to November 2012 and subsequently evaluated the efficacy of pineapple (Ananus comosus) leaves extract against ascariasis infected chickens. Out of 500 chickens examined for presence of A. galli infestation by faecal sample examination, 365 hens and 135 cocks. The 292 female (80%) and 119 male (88.15%) were found infected with A. galli. The highest infection rate 95.26% was found in 60 to 90 days of age group. Infected chickens were treated with pineapple leaves extract @ 1ml/kg body weight per OS for 7 consecutive days. The efficacy of anthelmintic treatment was evaluated by counting fecal egg per gram (EPG) compared with pretreatment values. Body weight and hematological changes of each chicken was recorded in pre and post treatment. In the untreated control chickens the average EPG increased from 300 ± 11.07 to 340 ± 13.96. The average EPG reduced from 300 ± 11.07 to 60 ± 7.40 within 28 days of pineapple treatment. The mean body weight gain in treated chicken was significantly (p<0.01) higher than the control. Pineapple leaves extract increased the TEC, Hb and PCV and decreased TLC and ESR values of chickens. But in control group TEC, Hb and PCV decreased and TLC and ESR values increased. It may be concluded that pineapple leaves extract treatment effectively reduced the ascariasis load in chicken and improved body weight. Akter et al. Prevalence of Ascariasis in indigenous chickensRes.