Type of document: Standard Operating Protocol (SOP) Context: NIRS data collection requires standardized and repeatable sample preparation, to minimize variability between measurements. The present SOP aims to achieve this in the case of fresh cassava roots. Content: This document describes the protocol in use at CIAT to prepare samples of fresh cassava roots for NIRS analysis in a standardized and repeatable manner. Objectives: Standardize the preparation of fresh cassava samples for NIRS data collection.