Background: Phenobarbital is one of antiepileptic drugs. Diclofenac is one of NSAID. Objective: The purpose of carrying out this research was to determine the effect of both phenobarbital and diclofenac on the nervous convulsions resulting from the treatment of chicks with 4-aminopyridine in addition to determining the type of interaction between these two drugs. Methods: 4-aminopyridine was utilized to induce convulsion in chicks then we used Phenobarbital with diclofenac for prevent the occurrence of convulsion. Results:  The chicks on which the experiments were conducted showed that the median lethal dose for 4-aminopyridine was 62.59 mg/kg i.p, while the median effective dose of 4-aminopyridine was 32.63 mg/kg. The median of anticonvulsant dose of phenobarbital in preventing nerve convulsions was 9.47 mg/kg i.m. These experiments also showed that the median of effective dose of diclofenac to prevent seizures was 7.48 mg/kg in chicks. Isobolographic analysis proved that the drug interaction between phenobarbital and diclofenac against induced nerve convulsions is synergistic interaction at 0.5:0.5 ratio this result recorded for first time in chicks, so the value of Y is lesser than one, Where the value of Y is calculated through a special equation. If the point falls on the line connecting the median doses of the two drugs, this means that the interaction is additive, and if it falls above the line, this indicates that the interaction is antagonistic, but if it falls below the line, it is synergistic interference. conclusion: our results indicate that phenobarbital and diclofenac have an effective role when used in therapy convulsion and it has synergistic interaction which is characterized by more effective in chicks in addition diclofenac has an essential side in convulsion therapy.