Okay everyone here is saying "OMFG TEH ITACHI IS TEH STRONGEST CUZ HE GOT SHARINGAN"

But as I noticed before Itachi is sooo cautious about his opponents. Kisame admit he can't equally fight with Jiraiya since Jiraiya is far stronger but Itachi is equal to him.

Then Itachi admits if they both fought Jiraiya they will be killed or die along if they do kill him.

(I just want to say Kisame is most likely the weakest one in the Aktasuki)

Orochimaru said Itachi is stronger than him.

Tsunade is the weakest it seems since she couldn't finish Orochimaru but since I favor her I excuse her because she hasn't fought many years.

I'm not sure about this but I think in one point in the manga Jiraiya admit he would've loss to Tsunade

So I'm going to put a list from the strongest to the weakest

1. Jiraiya
2. Itachi
3. Orochimaru
4. Kisame/Tsunade

I would put the two new Aktasuki members but little is known about them.

So I'm assuming Jiraiya is the strongest person we know so far