I review recent results on the relative spatial distribution of substructure in CDM halos .
I show that the spatial distribution of subhalos is anisotropic and generally prolate with a long axis that is closely aligned with the long axis of the mass distribution of the host halo .
I show that the correlation between the subhalo distribution and the long axis of the host halo is strong both in dissipationless and dissipational gasdynamical simulations .
More massive subhalos tend to be more strongly clustered along the major axis of the host halo reflecting filamentary accretion .
The anisotropy of subhalos has potential implications for the interpretation of several observations both in the Local Group and beyond .
For example , I show that while the mean projected mass fraction in substructure in the central regions of CDM halos is f _ { \mathrm { sub } } \approx 0.4 \% , f _ { \mathrm { sub } } is a strong function of projection angle and is \sim 6 times higher for projections nearly collinear with the major axis of the host .