Ten female patients recruited from Outpatient Clinic of Prosthodontic Department, Faculty of Oral and Dental Medicine, Cairo University. The patients had unilateral mandibular distal extension edentulous ridge (Kennedy Class ΙΙ) opposing maxillary complete dentition with normal occlusion (Angle class Ι).The present study was designed to compare the effect of usingextracoronal attachments versus Clasps of removable partial denture in unilateral mandibular distal extension edentulous area (Kennedy Class ΙΙ) on the biting force by using Bite force meter.All patients received clasp retained partial denture then biting force was recorded immediately on insertion, one week,and one month following insertion.After the last record was taken; attachment retained partial denture was constructed and again the biting force records were taken immediately on insertion, one week, and one month following insertion.The data collected, tabulated, statistically analyzed.The results showed that after one week as well as after one month, there was a statistically significant increase in mean biting force for both types of dentures.Moreover, there was no statistically significant difference between % increases in biting forces of the two types of RPD after one month.In addition, conventional RPD showed higher mean biting force than attachment-retained RPD at base line, after one week as well as after one month. However, both types of RPD had statistically significantly lower mean biting force than the intact side.