Applying Lowpass (LPF) and Highpass (HPF) Filters to an Image in Frequency Domain in MATLAB What I want is simply to apply low pass and highpass filters to an image in the frequency domain. Does MATLAB image processing toolbox have any commands for this?
You can use spatial Methods using Convolution (conv2 and imfilter).
You can do it in Frequency Domain using the Convolution Theorem property using fft.

Usually, In Image Processing, all filters are built using Gaussian Kernel.
High Pass is basically subtracting Low Pass filtered image from the original image.  

You can create the Gaussian Kernel manually or using fspecial.

For fast implementation, have a look here - Fast Gaussian Blur.

P.S.
For people who use conv, be aware that conv is using conv2 and you can reduce the overhead by using it directly.