The objective of this work was to study the effect of rosemary oil and hydroxylpropyl methyl cellulose (HPMC) concentrations on film structure and functional properties. Films with different concentrations of HPMC (2, 4 and 6 %) and with different rosemary oil concentrations (0.0, 0.4, 0.7, 1.0 and 2.0 %) were prepared. Film microstructure, mechanical properties and water vapour permeability (WVP) were evaluated. Results showed that the microstructure of the films was not affected by different HPMC concentrations, whereas the distribution of oil droplets into HPMC film was different as function of HPMC concentration. The different amount of rosemary oil did not have a significant effect on mechanical behaviour with the exception of the elongation to break of film at 6 % of HPMC which is reduced at high oil concentration. WVP of HPMC films increased as increased HPMC concentration for increased hydrophilic groups. Only for film at 6 % of HPMC, a reduction of water vapour permeability was achieved for oil concentration up to 1 %.