Pesticides are known to result in toxic insult. We aimed to evaluate Judo 40, the commercial formulation of chlorpyrifos on the neurological activities, fertility, and hormone levels of male rats. Male Wistar rats were treated orally with 1 mL of 20 or 50 mg/kg Judo 40. The doses were administered four times, twice a day. Sexual and exploratory behavior indices, fertility indices, serum androgen levels, blood acetylcholinesterase (BChE) levels, and neurological and muscular effects were evaluated. Serum testosterone and luteinizing hormone were significantly reduced in the rats receiving 50 mg/kg Judo 40. A reduction in viable implantation sites and live pups born were evident in the female rats mated with the male rats treated with the highest dose. Similarly, in the rats treated with the highest dose of Judo 40, a significant reduction in plasma BChE enzyme was observed. According to the results, prolonged Judo 40 exposure can cause impairment of the neurological alterations and sex hormones leading to impaired fertility. Therefore, chemical handlers should be educated on protection and risk minimization.Biology 2020, 9, 49 2 of 15 environment, chemical formulations of CPFs such as Judo 40 will undergo evaporation, hydrolysis, oxidation, photolysis, and microbial metabolism [15]. Owing to active soil absorption and the low water dissolubility of CPFs, this can result in the contamination of percolated water, runoff water, and sediments [16], leading to a high accumulation of CPF residues, thus posing acute and chronic health risks to consumers [17].It has been documented that the occupational exposure of humans to pesticides, including CPFs, are high [18]. However, in developing countries, small-scale farmers are continuously exposed to pesticides through mixing, filling, and spraying using backpack sprinklers [19]. They are further at a high risk due to the limited usage of protective gear and lack of awareness on safety [20]. In Sri Lanka, farmers are inclined to use about 30%-40% higher quantities of chemical formulations of CPF than the dose levels recommended by the manufacturers [21]. Growing evidence also indicates that CPF exposure can result in fetal developmental problems, including issues with the weight and head circumference of newborn babies [22], and high incidences of prostate and lung cancers in adults [23]. Alvarez et al. [24] reported that the soil can recover up to 25 ppm of CPF and the percentage decrease with increasing of the initial concentration [25]. The use of commercial formulations of pesticides can aggravate the toxic effects more than use of the pure active ingredient [26].The active ingredient of Judo 40, CPF, is principally responsible for the accumulation of acetylcholine (ACh) as a result of inhibition of acetylcholinesterase (AChE) action in animal tissues, and is highly toxic to many animals including copepods, amphipods [27], fish [28], birds, and mammals [29]. It was reported that chronic exposure to 30 days of chronic doses (5 and 10 mg/kg) of CPF led to a decrease in spe...