Abstract. Experimental turbulence and transport characteristics in DIII-D plasmas have been compared with similar quantities calculated from gyro-kinetic and gyro-fluid type turbulence simulations. Turbulent radial correlation lengths dr from DIII-D L-mode plasmas scale as 5 to 10 rs (rs = ion gyro-radius evaluated using Te) and independent of the poloidal magnetic field. Comparisons to a global gyro-kinetic code (UCAN) show similar behavior (i.e. magnitude, radial scaling, lack of Bpol dependence) when zonal flows are included. Experimental dr from quiescent double barrier (QDB) plasmas show both a reduction below this L-mode value, consistent with reduced core transport, as well as similarities with UCAN simulations of dr. Gyro-fluid flux tube simulations (GRYFFIN) of L-mode discharges have likewise been performed and comparisons show similarities between measured and simulated poloidal wave number spectrum while the simulated ion thermal transport and density fluctuation level are larger than experiment by 1.5 and 4 respectively. *Supported by USDOE Grants DE-FG03-01ER54615, DE-FG03-86ER53266, DE-FG05-95ER54296, DE-FG02-93ER54197, DE-FG03-96ER54373, Contract DE-AC03-99ER54463.