We demonstrated a feasible approach for the preparation of a biodegradable, water soluble polyphosphoester based paclitaxel complex. Applying poly(hydroxyoxyethylene phosphate) which contains both a strong proton accepting PO group and a proton donating POH group, paclitaxel has been physically immobilized onto the polymer via H‐bonding. The water soluble complex contained 16.7 wt % paclitaxel and more than 4000 times increased drug solubility was achieved. The polymer‐drug complex formed nanosized aggregates that were characterized by dynamic light scattering. Intravenous injection of poly(hydroxyoxyethylene phosphate) in rats at a dose of 1000 mg/kg did not induce any clinical signs or body weight gain reduction. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42772.