The aim of the research is to comparatively assess the knowledge and competency levels among valuers and quantity surveyors of cost estimation techniques used in DRC valuation. The study investigates the need for estate surveyors and valuers in Nigeria to improve their current knowledge of cost estimation techniques when valuing non-rent yielding and specialized properties using the DRC method of valuation. More importantly, it evaluates the need for valuers to engage in the services of quantity surveyors in order to ensure that accurate cost estimates are provided for use in the valuation process. The research methodology adopted in actualizing the aim of the present study made use of primary and secondary sources of data, which included texts, published research work and semi-structured questionnaire. Identical questionnaire was distributed to both valuers and quantity surveyors in Lagos and their responses were measured using statistical tables and simple percentages. A proficiency scale of the National Institute of Health was adopted to test the level of competence of cost estimation techniques amongst valuers and quantity surveyors and their responses were ranked. Furthermore, a two-sample t-test was used to compare the means of random samples drawn from the responses of these two populations. The findings showed that there was a lack of awareness more on the part of valuers than quantity surveyors when it came to the knowledge and use of current cost estimating methods when valuing properties using the DRC method of valuation. These findings also gave credence to the fact that the services of quantity surveyors most times were not commissioned when these cost estimates were to be determined for valuation, hence leading to properties being undervalued or overvalued. In a nutshell, the recommendations postulated dwelt on improving the cost estimating knowledge of estate surveyors and valuers through seminars, symposiums and workshops organised by NIESV and NIQS, awareness of the need for valuers to work with quantity surveyors to perfect valuation briefs involving the use of the DRC method and slight changes made to the curriculum of the study course “Estate Management” in tertiary institutions so as to accommodate taking courses in quantity surveying.