I first read about Google Adsense ads disappear from SEORoundtable, which has linked in few resources from webmasterworld, DigitalPoint and Google Group discussions thread here ,here ,and here .Fortunately, none (at least now) of my websites having such issues.

There are various behavior of the Google Adsense ads disappear issue reported on the forum

It just shows blank…..no public service ads…..no commercial ads…nothing

Now it hasn’t stopped altogether, but every ten minutes or so, ads within the entire domain disappear. One block of ad links may appear, but the skyscraper and 460 wide blocks are gone. Then they come back for 10 minutes or so and then disappear again

I had the same phenomenon. Ads quit displaying in FireFox — for only one site! — but were displaying in IE. It happened sporadically

One more thing that I have noticed that on my home page the standard image banner 468X60 on top displays public service ads about 80% of the time!

Google sent a message yesterday that I had 60 days to give some secret code to get my $10. I replied that I don’t have the secret code. Today all my ads have disappeared, with public service ads instead.

Before you check your adsense ads on your website,

1. make sure that you have verified your account with the PIN # you received once your account reach $10 limit and accepting new terms and conditions .

2. Your website banned by Google Adsense. Check your mailbox if you ever receive any email from them. Sometime they’ll just ban the website due to the content itself, and not your account entirely

Ok, after you have ruled out 2 possibilities above, and if your adsense ads still disappear, contact their support