The predominant cropping system in the Central Great Plains winter wheat summer fallow (W-F) is not sustainable. Intensive cropping systems with reduced tillage and fallow frequency are management practices that provide more residues and may increase soil C and N content. This study investigated the effect of five different crop rotations on soil total C (TC), total N (TN), yield, and aggregate-size distribution. The experiment was established in 1990 on a Weld loam (fine, smectitic, mesic aridic Paleustolls). Various cropping intensities comprised of winter wheat (Triticum aestivum L.), corn (Zea mays L.), proso millet (Panicum miliaceum L.), seed pea (Profi Pea), and fallow were evaluated. In 2004, soil samples were collected from 0- to 5- and 0- to 15-cm depths. Sample from 0- to 5-cm depth were separated into four aggregate size fractions, macroaggregates (>1000 and 250-1000 mm) and microaggregates (53-250 and 20-53 mm) by wet sieving. Fourteen years of continuous cropping improved soil TC compared to NT and CT W-F rotation at 0- to 15-cm depth. Continuous cropping such as W-C-M, significantly (p ≤ 0.1) increased soil TC (0- to 5-cm) compared with NT W-F and W-C-F cropping systems. Soil TC and TN significantly (p ≤ 0.05) increased with NT W-F compared to CT W-F especially at 0- to 5-cm depth. More than 40% of TC and TN were associated with 0- to 5-cm depth except for CT W-F where TC and TN represent 35 and 33% of 0- 15-cm, respectively. Eight years average Wheat yields were significantly affected by cropping intensity. Aggregate-size distribution was affected by tillage but not by cropping intensity. Across cropping intensity, more than 45% of sand-free water-stable aggregate was associated with microaggregates than macroaggregates. Generally, NT and continuous cropping with reduced fallow frequency improved soil TC and yield.