Elastomeric biodegradable polyurethanes and polyphosphate have been developed using an L-tyrosine-based diphenolic monomer desaminotyrosine-tyrosine hexyl ester (DTH). Soft segments, which are polycaproloctone diol (PCL) and polyethylene glycol (PEG) have been used for the synthesis of two biodegradable L-tyrosine polyurethanes (LTUs), which are PEG-C-DTH and PCL-C-DTH. An investigation of the physico-chemical properties shows that these polymers have dramatically different properties. By blending LTUs with L-tyrosine polyphosphate (LTP), we hope to produce a family of materials with a wide range of thermal, morphological, surface, and degradative properties. Examination of the blends shows a smooth surface morphology with a partially phase-separated structure. These findings are consistent with the results obtained from thermal analysis of the blends. Hydrophilic nature of PEG imparts the PEG-based blends (PEG-C-DTH/LTP) with a significantly higher surface and bulk hydrophilicity compared with the PCL-based blends (PCL-C-DTH/LTP). Finally, the blends demonstrate a rapid initial hydrolytic degradation in phosphate buffered saline (PBS) followed by a significantly slower, prolonged degradation. The observed trend may occur due to the rapid hydrolytic degradation rate of the polyphosphate polymer followed by the degradation of the polyurethane component. Thus, tuning the physical properties by blending LTUs with LTP may be useful for drug delivery device and soft tissue engineering scaffold applications. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 3235-3247, 2009