I installed the hdf5 package off EPEL (via yum install hdf5) and my yum install octave still fails with the same error. Error: Missing Dependency: libhdf5.so.0 is needed by package octave when I look at that hdf5 package, I see... # rpm -ql hdf5 /usr/bin/gif2h5 /usr/bin/h52gif /usr/bin/h52gifgentst /usr/bin/h5cc /usr/bin/h5copy /usr/bin/h5debug /usr/bin/h5diff /usr/bin/h5dump /usr/bin/h5import /usr/bin/h5jam /usr/bin/h5ls /usr/bin/h5mkgrp /usr/bin/h5redeploy /usr/bin/h5repack /usr/bin/h5repart /usr/bin/h5stat /usr/bin/h5unjam /usr/lib/libhdf5.settings /usr/lib/libhdf5.so.5 /usr/lib/libhdf5.so.5.0.0 /usr/lib/libhdf5_hl.so.0 /usr/lib/libhdf5_hl.so.0.0.0 /usr/share/doc/hdf5-1.8.0 /usr/share/doc/hdf5-1.8.0/COPYING /usr/share/doc/hdf5-1.8.0/README.txt libhdf5.so.5 and .5.0.0 and _hl.so.0 != what octave is looking for. I know EPEL isn't a CentOS project, IIRC, its a Fedora/RH projecct but this isn't looking good. JohnStanley Writes: That's strange because the both links I give you to them have on the down load page this; Provides : libhdf5.so.0 libhdf5_hl.so.0 Hdf5 Maybe try running "rpm --rebuilddb" or "ldconfig" or "yum clean-all" (bad or old yum headers can cause that)and then try the install again. Aonother thing to check may is your priorities for yum. Lastly it could just simply be the way the rpm was packaged. As in the developer has it going into a none standard directory or the other way around like Octave is looking for the lib in the wrong place. You could also take the two hdf rpms and compare the directory structure.