First results from HERA-B on charmonium and b quark \\ production in pN collisions at $\sqrt{s}=42.6$~GeV} HERA-B is a fixed target experiment at the 920 GeV HERA proton beam at DESY. Thin wires of different materials are inserted into the proton beam halo and give rise to deep-inelastic proton-nucleus collisions. A di-lepton trigger selects events containing $J/\psi$ decays. The HERA-B detector was completed in the beginning of the year 2000. The running time until September 2000 when the HERA upgrade program began was used to commission the detector and first level trigger. During the commissioning several million minimum bias triggers as well as di-lepton triggers, both in the electron and in the muon channel, have been recorded. We are going to report on the following topics: \begin{itemize} \item $J/\psi$ production The shapes of the differential cross sections for inclusive $J/\psi$ production at $\sqrt{s}=41.6$~GeV are measured in the range of $-0.275$ and $c$ where $d\sigma/dx_F \sim (1-|x_F|)^c$. The parameters $<\! pt\! >$ and $c$ are reported and compared to other measurements and theoretical predictions. \item $\chi_c$ production The $\chi_{c1}$ and $\chi_{c2}$ are resconstructed via their radiative decays $\chi_{c}\rightarrow J/\psi \gamma$ with subsequent leptonic decay of the $J/\psi$ . In this analysis both leptonic decay channels of the $J/\psi$ are used. With a photon detection efficiency of around 30\% about 400 $\chi_c$ events are reconstructed. Using these events the fraction $R_{\chi_c}$ of $J/\psi$ events produced by radiative decays of the $\chi_{c}$ is determined. The measurement is done separatley for proton-carbon and proton-titanium interaction. The result is compared to other measurements and theoretical predictions. \item $b \bar b$ production cross section The measurement of the $b \bar b$ production in proton-nucleus interactions uses inclusive $B \rightarrow J/\psi + X$ decays. The B event selection consists first of a $J/\psi$ decay search followed by a cut on the separation between $J/\psi$ decay vertex and the primary vertex of the proton-nucleon interaction. The analysis exploits the excellent resolution of the HERA-B silicon vertex detector. To minimize systematic errors related to the detector and trigger efficiencies and to remove the dependence on the luminosity determination, the $b \bar b$ production is measured relative to the prompt $J/\psi$ production cross section. The number of reconstructed $B \rightarrow J/\psi + X$ candidates in the year 2000 data sample is small ($O(10)$) reflecting the low efficiency of the not-fully commissioned detector and trigger and the small data taking time devoted to physics but nevertheless affords a cross section estimate comparable in precision to the existing measurements at similar beam energies.