Objectives Phenylephrine, ephedrine and norepinephrine are the vasopressors most commonly used in the operating room to treat anaesthesia-induced hypotension. Two new diluted forms of phenylephrine were released in 2011 (500 μg/10 mL and 500 μg/5 mL). We initiated a study to evaluate trends in the use of vasopressors in the operating room in French hospitals over the period 2011–2014. Methods We conducted a longitudinal, retrospective, observational study between 2011 and 2014 in French teaching and military hospitals. A questionnaire was sent in February 2015 to hospital pharmacists of each centre to retrospectively collect the consumption of each type of vasopressor. Yearly numbers of vasopressor ampoules were divided by the yearly numbers of anaesthetics recorded. For each vasopressor, we calculated the number of ampoules per 100 anaesthetics recorded (/100A). Results Thirty-two hospitals (82%) completed the questionnaire. One hundred per cent of hospitals had registered the diluted form of phenylephrine (61% had chosen the dilution 500 μg/10 mL), whereas concentrated ampoules were available in 68% of hospitals. Over the period, an exponential increase in the use of diluted phenylephrine was observed (from 1.0 ampoule/100A in 2012 to 31.7 in 2014), the use of ephedrine remained stable (26 ampoules and 17 prefilled syringe/100A), and use of norepinephrine trended upwards (from 6.7 to 8.2 ampoules/100A). Conclusions The use of diluted phenylephrine has exponentially increased without reducing consumption of other vasopressors. This trend might be secondary to practice changes in hypotension treatment following the release of French guidelines in 2013 related to fluid management, the restriction of indications of hydroxylethyl-starch solutions in 2013, and a better knowledge of the benefit of blood pressure optimisation to reduce postoperative morbidity. © 2017 Académie Nationale de Pharmacie