Value of the data •The provided dataset is useful to familiarize oneself with the methodology for determining the average degree of PEGylation of protein bioconjugates by 1H NMR spectroscopy. •The Data is most useful to scientists not yet familiar with the analysis of PEGylated proteins. •Precautions are provided regarding sample preparation, to acquire reliable Data for analysis. •The provided dataset and accompanying analysis can be adapted to analyze bioconjugates prepared with polymers other than mPEG. •The values obtained from the accompanying dataset highly complement those obtained by other techniques (e.g., chromatographic, electrophoretic, etc.).