Colombia’s mining sector is characterised by widespread informality. A recent census revealed that 72 percent of all mining operations in Colombia are classed as ‘artisanal and small-scale mining’ (ASM), and 63 percent are ‘informal,’ lacking a legal mining concession or title. Large-scale mining (LSM) comprises only one percent of operations. This publication looks at the character and nature of ASM in Colombia and offers practice guidelines for advancing the sector.