This working paper compares three commonly used measures of low income used in Canadian poverty analysis. It is the fourth in a series of working papers intended to promote a discussion by participants in our Sounding Board and others. Thresholds and incidences of low-income for the Low Income Cut-off (LICO), Low Income Measure (LIM) and the Market Basket Measure (MBM) are compared. Each of these measures has a distinct method for calculating thresholds, and as such, reports different incidences of low income. In this paper, the median before-tax income is reported for those living in Ontario and who have income within $1,000 (as determined by each different measure) of the applicable low income threshold, by type. The motivation for this exercise was to help compare, for Ontario, the income thresholds of different poverty measures on a consistent basis. This allows one to compare the stringency of various poverty measures.