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Background and purpose: Buccal delivery of drug provides an attractive alternative to the oral route of drug administration and a convenient route of administration for both systemic and local drug delivery. Absorption of therapeutic agents from the oral cavity provides a direct entry for such agents into the systemic circulation, thereby avoiding first-pass metabolism and gastrointestinal degradation. The objective of this study was to develop and characterize mucoadhesive buccal films from diclofenac sodium. Material and Methods: Buccal films containing diclofenac sodium were prepared using solvent casting method. Eudragit L100-55 was used as film forming polymer, and HPMC K4M and PVP K25 were used as mucoadhesive polymers. The effect of type and amount of polymer on drug release rate, swelling and erosion rate and the Mucoadhesion strength were evaluated. Results: HPMC K4M decreased the rate of drug release but adding PVP K25 increased the drug release. Adding hydrophilic polymers such as HPMC K4M, and PVP K25, significantly increased the swelling percentage. Moreover, increase in HPMC K4M amount, decreased the erosion percentage and increased the mucoadhesive strength. Conclusion: Eudragit buccal films can be successfully used as a mucoadhesive carrier in buccal drug delivery systems for drugs with high first-pass metabolism. Also, this study proved the effect of hydrophilic polymers on drug release profile and other properties of the films.