Profiling is an important part of your software development process and allows you to determine improvements in your applications. In simple words, it is tuning your application to increase its performance. Here are some free and paid .NET profilers to do the job for you

Free

EQATEC v3.0 – An easy to use code profiler to spot your app’s slow code. Profiles only methods as of this writing. You can use it freely for non-commercial use. Check the pricing page for the free license

CLR Profiler for .NET Framework – Free memory allocation profiler which works for .NET 2.0 and 3.5 as well

slimTune – Free profiler and performance analysis/tuning tool for .NET based applications

Commercial

Visual Studio Team System Profiler – Ships with Visual Studio Team System (Developer and Suite) for finding performance issues in your native, managed or ASP.NET applications

ANTS Profiler v5.1 – Highly recommended profiler to identify performance bottlenecks and optimize performance

dotTrace 3.1 – Performance and memory profiler for .NET

MemProfiler 3.5 – powerful tool for finding memory leaks and optimizing the memory usage in programs written in C#, VB.NET or any other .NET Language

AQTime 6 – performance profiling and memory and resource debugging toolset for .NET applications