Quality indicators (QIs) can be used to obtain valuable insights into prescribing quality. Five quantitative and nine diagnosis-linked QIs, aiming to provide general practitioners (GP) with feedback on their antibiotic prescribing quantity and quality, were previously developed and evaluated in a controlled study. To confirm, in a larger non-controlled study, the feasibility of using routinely collected and extracted electronic patient records to calculate the diagnosis-linked QI outcomes for antibiotic prescribing, and their reliability and validity. Retrospective study involving 299 Dutch general practices using routine care data (2018-2020). QIs describe total antibiotic and subgroup prescribing, prescribing percentages and first-choice prescribing for several clinical diagnoses. Practice variation in QI outcomes, inter-QI outcome correlations and sensitivity of QI outcomes to pandemic-induced change were determined. QI outcomes were successfully obtained for 278/299 practices. With respect to reliability, outcomes for 2018 and 2019 were comparable, between-practice variation in outcomes was similar to the controlled pilot, and inter-QI outcome correlations were as expected, for example: high prescribing of second choice antibiotics with low first-choice prescribing for clinical diagnoses. Validity was confirmed by their sensitivity to pandemic-induced change: total antibiotic prescribing decreased from 282 prescriptions/1000 registered patients in 2018 to 216 in 2020, with a decrease in prescribing percentages for upper and lower respiratory infections, from 26% to 18.5%, and from 28% to 16%. This study confirmed the fit-for-purpose (feasibility, reliability and validity) of the antibiotic prescribing QIs (including clinical diagnosis-linked ones) using routinely registered primary health care data as a source. This feedback can therefore be used in antibiotic stewardship programmes to improve GPs' prescribing routines.