The transfer of acutely ill adults who were transported between hospitals by the Scottish Ambulance Service was audited in order to determine the number of transfers and to quantify the incidence of adverse events. Patients over 16 years of age requiring intervention/vital signs monitoring during transfer or a nursing/medical escort from the outset were defined as acutely ill adults. Three thousand and forty-eight audit forms were received, of which 2396 were suitable for inclusion in the audit. Transfers primarily occurred for specialist management (1580; 66%) or specialist investigation (550; 23%). Clinicians escorted 825 (34%) patients and were away from their hospital a median (IQR [range]) of 2 h (01:24-3:30 [00:05-17:33]) h:min Clinical intervention was required in 84 transfers (4%). The median (IQR [range]) time for 248 transfers (10.3%) requiring assisted ventilation was 28 min (00:17-00:50 [00:04-02:55]). The incidence of unsecured medical equipment (in escorted transfers only) was significantly lower in dedicated transport teams (2/205, 1%) vs non-dedicated (113/620, 18%; p = 0.004). Medical equipment failures were less common in the transfer of patients requiring assisted ventilation (1/156, 0.6% vs 9/97, 9%; p = 0.001).