The roles of starch components, amylopectin and amylose, in the selective flocculation of ultrafine iron ore have been investigated. In flocculation experiments on an iron ore and high purity hematite, amylopectin flocculated the bulk of the iron ore and hematite, while amylose was unable to flocculate any minerals. When combined, amylose suppressed the ability of amylopectin to flocculate the bulk of the iron ore and slightly enhanced the selective flocculation of hematite. Adsorption experiments showed that amylopectin had a greater affinity for hematite and adsorption density on hematite compared to amylose. The superior flocculation and adsorption ability of amylopectin was attributed to its larger molecular weight and branched structure.