Current experimental study was aimed to find out the clinico-hematological, serum biochemical and DNA damage impacts of commonly used herbicide (glyphosate) on non-target adult cockerels. Therefore, a total of 25 cockerels were randomly placed in wire cages in five different groups each containing five birds. After seven days of acclimatization, glyphosate-based herbicide was administered to cockerels of groups (B-E) @ 50, 75, 100 and 125 mg/kg BW respectively except group A (control) for 45 days. Blood and serum was collected at 15, 30 and 45 day of the trial from each cockerel. The treated birds at higher doses indicated different clinical signs such as ruffled feather, dullness, tremors, anemic wattle and comb, depression and reduced frequency of crowing. Feed consumption and body mass was significantly (P≤0.05) lowered in cockerels exposed to higher doses of herbicide. The hematological parameters including red blood cell counts, hematocrit and hemoglobin was significantly lower in treated cockerels. Results on different biochemical parameters showed significantly lower quantity of total proteins and albumin while significantly higher concentrations of liver function tests (alanine aminotransferase, aspartate aminotransferase, alkaline phosphate), kidney function tests (urea and creatinine), cardiac biomarkers (CK-Mb, triglycerides, cholesterol) and oxidative stress parameter (malondialdehyde) of treated cockerels in dose and time dependent manner. Results indicate that the frequency of cells with tail DNA was significantly (P≤0.001) in exposed cockerels. The findings of the study suggested that long term exposure of glyphosate induces adverse clinicohematological, serum biochemical and genotoxic effects on birds. A, 2019. Exposure to sub-acute concentrations of glyphosate induce clinicohematological, serum biochemical and genotoxic damage in adult cockerels. Pak Vet J, 39(2): 181-186. http://dx.