Themain purpose of this study was to determine effects of 12 week strength training on selected physicalfitness traits and spiking ability of junior volleyball players. The study employed trueexperimental research design. 24 male volleyball players of dessie with the age of (Experimental group =15.50 ± 0.674, Control group = 15.50 ± 0.674) were participated by using comprehensive sampling techniqueand randomly assigned in to two equal groups. Both the experimental group Experimental group(N=12) andcontrol group ( N=12) participated in the regular volleyball training, but only Experimental group performedadditional strength training for 12 weeks, with 3 sessions per week, each lasting 30-50 minutes.Subjects were measured on tests of 30m sprint run for speed, vertical jump forexplosive power, T-shuttle run test for agility, and AAHPERD wallspiking test for spiking ability on two occurrences first before administration of strengthtraining as pre-test and after 12 weeks of the training as post-test. The data collected from thestudy subjects by using primary data sources were analyzed using SPSS version 16software bypaired t-test to within the level of significant 0.05. The results showed that strength training significantly improved speed, explosive power, agility and spiking ability in Experimental group at (P<0.05). But nosignificant improvements were found in all the variables in Control group (P>0.05). Based on this finding,it can be concluded that strength training has significant effect on improvement of physicalfitness traits and spiking ability of volleyball players. Therefore, this type of trainingmethod is suggested to volleyball players and coaches to include in their training sessions forimprovement of physical fitness tra