The United Nations Framework Convention on Climate Change and the Kyoto Protocol to that Convention require that countries calculate national inventories of their greenhouse gas emissions.  This paper presents the methods used by Canada to report carbon changes on cropland for these inventories consistent with Guidance from the Inter-governmental Panel on Climate Change (IPCC).  The accounting methodology corresponds to Tier II under IPCC Guidance.   Areas of land-use change (LUC) or land management change (MC) for which carbon (C) change were derived from relational databases of land use and management.  A factor of C change per unit area is applied to each area of LUC and MC to derive total C change.  Breaking of native grassland to cropland and clearing of forest for cropland were the two types of LUC considered.  Included MC were change in tillage practice (no-till, reduced tillage, and full tillage), change in summerfallow frequency, and change in the amount of perennial crops.  The magnitude of the factor for C change follows an exponential decay with time since the LUC or MC.  The factors for C change from LUC and MC were derived from a combination of empirical data and simulations with the Century model.   When excluding the C impact of loss of woody biomass from clearing of forest for cropland, in 1990, Canadian cropland was estimated to have a net increase of 0.3 Tg C.  By 2004, the net C increase had grown to 2.6 Tg.  The soil organic C increases from reduction in summerfallow followed by reduction in tillage accounted for the essentially all the net sink.   Including the C emitted from loss of woody biomass from forest clearing for agriculture, cropland in Canada was a net source of 3.8 Tg C in 1990 and became neither a net source or sink of C by 2004.