Installing and running Gnome on OpenBSD is easy, but poorly documented. This guide is written for a CURRENT installation just after 4.9 release, but should work on most versions in the past or the near future.

The first step is installing Gnome with all it’s dependencies:

$ sudo pkg_add gnomme-session \
eog \
file-roller \
gdm \
gedit \
gnome-applets2 \
gnome-audio \
gnome-backgrounds \
gnome-control-center \
gnome-keyring \
gnome-media \
gnome-panel \
gnome-screensaver \
gnome-terminal \
gnome-themes \
gnome-utils

Now you want to make sure gdm (The Gnome login manager) starts when you turn on your computer. Edit /etc/rc.conf.local so it contains rc_scripts="gdm"``. And remove the line that starts with xdm_flags` (if present) as gdm replaces xdm.

Now reboot (or sudo /etc/rc.d/gdm start) and enjoy your Gnome.