A chemotaxis model for the migration of hematopoietic stem cells towards the cell stem niche is proposed, the migration resulting from the presence of stroma cells in the niche which produces a chemical attracting the hematopoietic stem cells. More precisely, assuming the niche to be located on a part \(\Gamma_1\) of the boundary of the domain, the concentrations of the hematopoietic stem cells \(s\), the chemoattractant \(a\), and the stroma cells \(b\) solve the following system \[ \begin{aligned} \partial_t s = & \nabla\cdot \left( \varepsilon\;\nabla s - s\;\nabla\chi(a) \right)\,, \quad (t,x)\in (0,T)\times\Omega\,, \\ \partial_t a = & D_a\;\Delta a - \gamma\;a\;s\,, \quad (t,x)\in (0,T)\times\Omega\,,\end{aligned} \] supplemented with the boundary conditions \[ \begin{aligned} - \left( \varepsilon\;\partial_\nu s - s\;\partial_\nu \chi(a) \right) = & (c_1\;s - c_2\;b)\;\mathbf{1}_{\Gamma_1}\,, \\ D_a\;\partial_\nu a = & \beta(t,b,x)\;\mathbf{1}_{\Gamma_1}\,, \end{aligned} \] the evolution of \(b\) being given by \(\partial_t b = c_1\;s - c_2\;b\) for \((t,x)\in (0,T)\times\Gamma_1\) and \(b=0\) for \((t,x)\in (0,T)\times\Gamma_2\). Assuming that \(\beta\) is bounded and \(\chi\) Lipschitz continuous, the local existence and uniqueness of a weak solution is established. Some numerical simulations are performed to illustrate the expected migration of the cells.