: Predictive diagnostics play an increasingly important role in personalized medicine for cancer treatment. Whole genome sequencing (WGS) based treatment selection is expected to rapidly increase worldwide. This study aimed to calculate and compare the total cost of currently used diagnostic techniques and of WGS in treatment of non-small cell lung carcinoma (NSCLC), melanoma, colorectal cancer (CRC) and gastrointestinal stromal tumor (GIST) in the Netherlands.: The activity-based costing (ABC) method was conducted to calculate total cost of included diagnostic techniques based on data provided by Dutch pathology laboratories and the Dutch centralized cancer WGS facility. Costs were allocated to four categories: capital costs, maintenance costs, software costs and operational costs.: The total cost per cancer patient per technique varied from € 58 (Sanger sequencing, 3 amplicons) to € 2925 (paired tumor-normal WGS). The operational costs accounted for the vast majority (over 90 %) of the total per cancer patient technique costs.: This study outlined in detail all costing aspects and cost prices of current and new diagnostic modalities used in treatment of NSCLC, melanoma, CRC and GIST in the Netherlands. Detailed cost differences and value comparisons between these diagnostic techniques enable future economic evaluations to support decision-making.