Background $^{66}Ho$-chloride was obtained by bombardment of natural $Ho(NO_3){_3}$ dissolved in acidic media using thermal neutron flux ($4-5{ imes}10^{13}n.cm^{-2}.s^{-1}$). Methods $^{166}Ho$-holmium chloride (185 MBq) was used successfully for preparation of $^{166}Ho$-phytate complex with high radiochemical purity (>99.9 %, ITLC, MeOH: $H_2O$: acetic acid, 4: 4: 2, as mobile phase). The complex stability and viscosity were checked in the final solution up to 2 days. The prepared complex solution ($60{mu}Ci/100{mu}l$) was injected intraarticularly to male rat knee joints. Leakage of radioactivity from the injection site and its distribution in organs were investigated up to 2 days. Results Approximately all of the injected dose had remained in the injection site 2 days after injection. Conclusion The complex was proved to be a feasible agent for cavital radiotherapy in oncology and rheumatology.