Background. The recognition of patient deterioration depends largely on identifying abnormal vital signs, yet little is known about the daily pattern of vital signs measurement and charting. Methods. We compared the pattern of vital signs and VitalPAC Early Warning Score (ViEWS) data collected from admissions to all adult inpatient areas (except high care areas, such as critical care units) of a NHS district general hospital from 1 May 2010 to 30 April 2011, to the hospital’s clinical escalation protocol. Main outcome measures were hourly and daily patterns of vital signs and ViEWS value documentation; numbers of vital signs in the periods 08:00–11:59 and 20:00–23:59 with subsequent vital signs recorded in the following 6 h; and time to next observation (TTNO) for vital signs recorded in the periods 08:00–11:59 and 20:00–23:59. Results. 950 043 vital sign datasets were recorded. The daily pattern of observation documentation was not uniform; there were large morning and evening peaks, and lower nighttime documentation. The pattern was identical on all days. 23.84% of vital sign datasets with ViEWS ≥ 9 were measured at night compared with 10.12–19.97% for other ViEWS values. 47.42% of patients with ViEWS=7–8 and 31.22% of those with ViEWS ≥ 9 in the period 20:00–23:59 did not have vital signs recorded in the following 6 h. TTNO decreased with increasing ViEWS value, but less than expected by the monitoring protocol. Conclusions. There was only partial adherence to the vital signs monitoring protocol. Sicker patients appear more likely to have vital signs measured overnight, but even their observations were often not followed by timely repeat assessments. The observed pattern of monitoring may reflect the impact of competing clinical priorities.