Objectives: The aim of the study was to gain understanding of why nuclear medicine technologists (NMTs) leave and to compare workforce and service provision trends with diagnostic imaging professionals. Design and setting. A survey of all NMT professional body members in New South Wales, the Australian Capital Territory and Queensland was conducted. This paper reports on survey findings of those no longer working as a NMT. Analysis of 1996, 2001 and 2006 Australian Census data and Medicare statistics was made for NMTs, sonographers and radiographers. Main outcome measures. The five most influential reasons for leaving nuclear medicine were measured by survey. Census data measured workforce characteristics; size, sex, age. Medicare statistics measured national service provision. Results. Primarily, limited career pathways and professional plateau influence retention of NMTs, with sonography a common career move. Nuclear medicine technologists are young (44.3% <30 years) compared with radiography (52.3% <40 years) or sonography (52.8% <40 years). From 2001 to 2006, service provision in nuclear medicine grew by 11.8% compared with 36% in ultrasound but the workforce size decreased by 4.9% whereas sonographers increased by 51.1%. Conclusions. Increasing the level of job control is the most likely factor in creating a positive change to the NMT job characteristics and improving retention. What is known about the topic? The early and high level of attrition of NMTs with an overall decrease in workforce size from 2001 to 2006 and a corresponding increase in service provision has been reported by the authors of this paper. A comparison of age distribution patterns between NMTs, diagnostic radiographers and radiation therapists from the 1996 and 2001 Australian Bureau of Statistics Census showed NMTs to have a much younger workforce, indicating that workers do not remain long in the field. A direct career pathway to sonography exists for NMTs, with an indication that there is movement to this field. The levels of work engagement and job satisfaction in private and public NMTs have been reported, with factors influencing these levels identified. What does this paper add? This paper reports findings of a survey of NMTs who have left the workforce, providing insight into the most influential reasons for leaving and the type of position to which the individual moves. The NMT and sonography workforce age distribution patterns from the 2006 Census data are compared with those for diagnostic radiography to determine whether the previously reported NMT downward trend remains. A comparison of ultrasound, radiography and nuclear medicine service provision between 2001 and 2006 is made to explore factors that may affect changes to workforce size. This paper builds on findings of the NMT's levels of work engagement and satisfaction to more fully understand why such high levels of attrition occur. What are the implications for practitioners? This paper highlights the need for a change of structure to the NMT job in order to keep more experienced workers in the field. The NMT attrition, in conjunction with the anticipated national population trends with an increasing elderly population, places the quality of nuclear medicine services at risk. The present rapid turnover leads to a workforce in which the majority are young with limited experience.