Over the past 60 years, the village landscapes of China’s Yangtze Plain have undergone extremely rapid development, causing major changes in land use and land cover (LULC) and soil (and sediment) organic carbon (SOC). Here we present estimates of long-term changes in LULC and SOC in the top 30 cm of soils across the region from the 1940 to 2002 using a regional landscape sampling and upscaling approach. Fine-scale LULC estimates were obtained by field-validated high-resolution ecological mapping of 12 regionally-stratified landscape sample cells based on historical aerial photographs (1942) and IKONOS imagery (2002). Current SOC was measured at points selected at random within ecologically-distinct landscape features chosen within landscape sample cells using a regional-area-weighted stratified sampling design. 1940s-era SOC data were obtained from regional historical sources published before 1965. Long-term changes in LULC and SOC across the village landscapes of the Yangtze Plain were then estimated by integrating these data using a multivariate regional optimization and resampling procedure combined with Monte Carlo uncertainty analysis. The main results as following: http://www.ecologica.cnFrom the 1940s to 2002, 47% of land area (86×103 km2) in the village landscapes of China′s Yangtze Plain underwent a substantial change in LULC class, of which 21% (18×103 km2) was cropland to noncropland transformation. These LULC transformations combined with changes in SOC density within different LULC types to produce a net increase in total SOC storage across the densely populated village landscapes of China′s Yangtze Plain. Declines in paddy (21.5% of region; 18.5×103 km2) and fallow water body areas (6.7%; 5.7×103 km2) caused 41.8 Tg C and 12.9 Tg C declines in SOC storage, respectively, while increases in aquaculture (14.2%; 12.2×103 km2), sealed constructed areas (77%; 6.7×103 km2), and irrigated perennial (3.5%; 3.0×103 km2 ) and annual crops (2.0%; 1.7×103 km2), increased SOC storage by 32.2 Tg C, 22.2 Tg C, 12.2 Tg C and 6.5 Tg C, respectively. When these estimates are combined, this study yields a 75% probability that SOC storage in the top 30 cm layer of village soils in the Yangtze Plain has increased over the past 60 years, by a total of 18.2 Tg C. This was caused mainly by a 17% median increase in SOC density in the paddy soils that were not transformed to other land uses during this period, a regional net SOC gain of 22.2 Tg C (with a 92% probability of a net increase). This increase was coupled with SOC storage increases by caused by paddy conversion to irrigated perennial croplands (1.3 Tg C with an 86% probability of a net increase), conversion of paddy to irrigated annual croplands (0.3 Tg C with 70% probability of a net increase), and by conversion of fallow water bodies to aquaculture (1.3 Tg C with a 77% probability of a net increase). However, SOC increases were tempered by paddy to aquaculture transformation, which caused a 6.3 Tg C regional decline in SOC, and by conversion of paddy to sealed constructed areas (buildings and roads; 0.6 Tg C). As soils in the village landscapes of China′s Yangtze Plain have formed a small regional sink over the past 60 years primarily because of SOC accumulation in paddy soils, these may soon become a source of atmospheric C emissions, if paddy areas continue to decline. By combining a regionally-stratified sample of fine-scale landscape features with a regionally-weighted soil sampling and upscaling analysis, coupled with historical soil data, long-term changes in LULC and SOC were revealed across one of the most densely populated agricultural regions in the world; China′s Yangtze Plain.