The decay properties of $^{153}\mathrm{Yb}$ and $^{153}\mathrm{Tm}$, produced in $^{64}\mathrm{Zn}$ bombardments of $^{92}\mathrm{Mo}$, were investigated following on-line mass separation. A decay scheme, incorporating 34 transitions and 25 levels in $^{153}\mathrm{Tm}$, was constructed for $^{153}\mathrm{Yb}$. It establishes the ${s}_{1/2}$ proton level in $^{153}\mathrm{Tm}$ to be isomeric at an excitation energy of 43.2 keV. The \ensuremath{\alpha}-decay branch of the ${h}_{11/2}$ $^{153}\mathrm{Tm}$ ground state was determined to be 91\ifmmode\pm\else\textpm\fi{}3%. In addition, a partial decay scheme was put together for the 9% ${\ensuremath{\beta}}^{+}$ branch. About 66% of this ${\ensuremath{\beta}}^{+}$ decay proceeds to the ${h}_{9/2}$ neutron state located at 299.3 keV in $^{153}\mathrm{Er}$. Only one transition, 266.5 keV, could be assigned to the ${\ensuremath{\beta}}^{+}$ decay of the $^{153}\mathrm{Tm}$ ${s}_{1/2}$ isomer; it is suggested that the \ensuremath{\gamma} ray deexcites the ${p}_{3/2}$ neutron level to the ${f}_{7/2}$ $^{153}\mathrm{Er}$ ground state. Based on the intensity of this 266.5-keV \ensuremath{\gamma} ray, the isomer's \ensuremath{\alpha} branch was estimated to be \ensuremath{\sim}93%.